What Should I Spend on Getting New App Users?

Getting new users for your app costs money, and working out how much to spend can feel overwhelming when you're staring at all those different marketing channels and trying to predict what might work. The question isn't really whether you should spend money on user acquisition, it's about spending the right amount in the right places at the right time, which I've learned through building apps for healthcare companies spending £50k a month on ads and bootstrapped startups running on just a few hundred quid.

Most app founders either spend too little and wonder why nobody downloads their app, or spend too much too quickly and run out of money before they've figured out what actually works

The mobile app space has changed massively over the past ten years, back when having any sort of paid user acquisition strategy meant you were ahead of the curve, but now you're competing with companies that have entire teams dedicated to performance marketing and millions in their budgets. Your spending needs to match your stage, your monetisation model, and your ability to turn new users into long-term customers who actually make you money... not just install numbers that look good in a pitch deck but don't pay the bills.

Understanding User Acquisition Cost Basics

User acquisition cost means exactly what it sounds like, the amount you spend to get one person to install and open your app for the first time. You calculate it by taking your total marketing spend and dividing it by the number of new users you got during that period, so if you spent £1,000 and got 500 installs, your CAC is £2 per user.

The tricky bit is deciding what counts as marketing spend. Do you include your time? The cost of creating assets? App store optimisation work?

I've worked with probably forty different apps on their user acquisition strategy, and the ones that succeed are ruthlessly honest about tracking every pound they spend. That means paid ads, influencer payments, content creation costs, agency fees if you're using one, and even the tools you're paying for like analytics platforms or ad management software. Understanding how to split your marketing budget across different channels is crucial for tracking meaningful CAC metrics.

These numbers shift constantly based on your targeting, creative quality, and how competitive your category is, but they give you a starting point for planning. A fintech app I built last year started with a CAC of £8.50 through Facebook ads, but we got it down to £4.20 over three months by testing different audiences and improving the onboarding flow so more people actually completed registration.

Setting Your First App Marketing Budget

When you're just starting out, you need enough money to actually learn something useful from your tests, but not so much that you're betting the farm on unproven channels. I usually recommend starting with at least £1,500 to £3,000 for your first proper paid user acquisition test, spread across maybe two or three channels so you can compare what works.

Anything less than a grand and you're just not getting enough data. You might get lucky. You might waste it all.

The apps I've seen succeed with smaller budgets are the ones that spend six to eight weeks doing free user acquisition first, building up some baseline data about who their users are, what messaging works, and where their audience hangs out online. Building an email list before launch is one of the most effective ways to establish this baseline data without spending money on paid ads. Then when they start spending money on paid channels, they've got something to compare against and they're not shooting in the dark.

Set your first paid marketing budget at 10-15% of your total available funds, never more, because you need runway to iterate based on what you learn from those first campaigns

A healthcare app we launched needed users to trust it with sensitive medical information, so we started with just £2k testing different messaging angles on Facebook. The winning creative focused on NHS-trained practitioners rather than the technology behind the app, which we never would have guessed without testing, and that insight shaped everything we did afterwards with a much bigger budget.

What Influences User Acquisition Costs

Your CAC isn't random, it's shaped by dozens of factors that interact in ways that can be hard to predict until you're actually running campaigns. The biggest factor is your target audience, trying to reach wealthy professionals in London costs more than reaching students in Manchester, and trying to reach people interested in investing costs more than reaching people interested in casual games.

Competition in Your Category

If you're building a meditation app, you're competing with Calm and Headspace who have massive budgets, which drives up costs for everyone trying to target the same keywords and audiences. I worked on an education app that pivoted slightly to focus on professional development instead of general learning, and the CAC dropped by 40% overnight because we moved into a less crowded space. Choosing the right app store category can significantly impact how much competition you face and therefore your acquisition costs.

Your App's Onboarding Experience

This is something people forget when they're thinking about acquisition costs. If half your new users bail during registration, your real CAC is double what the numbers say, because you're paying for people who never become actual users. We reduced CAC by 30% for an e-commerce app just by cutting the sign-up process from five screens to two, nothing else changed about the ads.

• Platform choice matters, iOS users generally cost more to acquire but spend more in apps
• Seasonality affects costs, December is expensive for shopping apps but cheap for fitness apps
• Creative quality can change your CAC by 200-300% with the exact same targeting
• App store ratings and reviews affect conversion rates from your ads

The time of year you launch your acquisition campaigns makes a bigger difference than most founders realise. I've run the same campaign in March and then again in November and seen completely different results, sometimes double the cost per install during competitive periods.

Free vs Paid User Acquisition Methods

Free user acquisition isn't actually free, it just costs time instead of money, and for most founders time is more valuable than they want to admit. App store optimisation, content marketing, social media building, PR outreach, all of these can bring in users without spending money on ads, but they're slow and they require consistent effort over months. Writing blog posts that drive downloads is one content marketing approach that can generate organic traffic over time.

The apps that grow sustainably use free methods to figure out their messaging and audience, then use paid methods to scale what's already working

I built an app for a fitness company that spent their first four months doing nothing but organic Instagram content and SEO for their website. They got about 50 installs a week. Doesn't sound like much.

But they learned exactly what content resonated, what objections people had, what features people asked for, and when they finally started spending £5k a month on paid acquisition, they knew exactly what to say and who to target. Their CAC was half what it would have been if they'd started with paid from day one.

When Free Methods Make Sense

If you've got more time than money, if your target audience is reachable through content or community building, or if you're still figuring out your core value proposition, start with free acquisition. I've seen apps grow to 10,000 users purely through word of mouth and good old-fashioned hustle, building relationships with people who then told their friends.

When to Start Paying for Users

Once you've got some evidence that people want what you're building, once you've got a retention rate above 30% after seven days, once you know roughly what a user is worth to you, that's when paid acquisition makes sense. Paying to acquire users into a leaky bucket just means you're burning money while you watch people leave.

Calculating Your Customer Lifetime Value

You can't make smart decisions about user acquisition spending without knowing how much each user is worth to you over time, not just on day one but across their entire relationship with your app. Customer lifetime value tells you the total revenue you'll make from an average user, which then tells you how much you can afford to spend acquiring them.

The basic calculation takes your average revenue per user per month, multiplies it by your average customer lifetime in months, then multiplies that by your gross margin. So if users spend £5 a month, stay for 12 months on average, and you keep 70% after costs, each user is worth £42 to you over their lifetime.

Now you know you can spend up to £42 acquiring each user and break even. Most apps aim to keep CAC at 30-40% of LTV, so in this example you'd want your user acquisition cost around £12-17 per user to have a healthy business. Pricing your app competitively plays a crucial role in determining these lifetime value calculations.

I worked on an app that was spending £8 to acquire users who were worth £85 over their lifetime, which looked great on paper, but they were running out of money because it took six months to make back that £8. Understanding not just LTV but how quickly you recover your acquisition costs matters just as much, especially if you're bootstrapped or running on limited funding. Be aware that app costs increase as you scale, which can impact your payback periods.

When to Increase Your Marketing Spend

Knowing when to pour more money into user acquisition is one of the hardest calls you'll make, do it too early and you're scaling something that doesn't work yet, do it too late and you're leaving growth on the table while competitors grab your potential users. I've been on both sides of this mistake.

The right time to increase spending is when you've got three things nailed down, first your retention metrics are stable and acceptable for your category, second you've paid back your CAC in a reasonable timeframe through user monetisation or engagement, and third you've got at least two acquisition channels that are working reliably so you're not dependent on one platform that could change its algorithm tomorrow.

Only increase your marketing budget when your CAC is at least 3x lower than your LTV and you're seeing consistent results over at least 30 days, not just one good week that might be a fluke

For a subscription app, I'd want to see 40% of users still active after 30 days, and I'd want to be recovering the CAC within three months of acquisition. For a transaction-based app, I'd want to see 25% of users making a purchase within their first 14 days, and the average purchase value needs to be at least 2x the CAC.

• Your current channels aren't maxing out, you can still scale them profitably
• You've got operational capacity to handle more users without service degrading
• Your unit economics improve slightly as you scale, not get worse
• You've got enough cash runway to sustain the higher burn rate for six months minimum

I worked with an app that tripled their marketing spend from £10k to £30k monthly when they hit these markers, and their CAC actually went down by 15% because they could bid more competitively and get better ad placements. But I've also seen apps double their spend and watch their CAC shoot up 60% because they'd already picked the low-hanging fruit and were moving into more expensive audience segments.

Common Budget Mistakes App Founders Make

The biggest mistake I see, probably in six out of ten apps I work with, is spending money on user acquisition before the app is actually ready. They've built something that technically works but the onboarding is confusing, the core features are buggy, or the value proposition isn't clear, and they think paid marketing will solve these problems. It won't. It just means you're paying to show people something that isn't good enough yet.

Spreading Budget Too Thin

Trying to test five different channels with £500 each gives you nothing useful, you can't learn anything meaningful from such small tests. Better to put £2,000 into one or two channels and actually get enough data to make decisions. I watched an app waste £3k across seven different platforms and learn absolutely nothing, then they spent the same £3k on just Facebook and Google and got clear winners they could scale.

Ignoring Cohort Analysis

Looking at your overall user numbers and saying you acquired 1,000 users at £4 each hides what's really happening. Maybe your first 500 users cost £2 but your next 500 cost £6, or maybe your December users all churned while your January users stuck around. Track each batch of users separately so you know which campaigns and time periods brought in the valuable users versus the ones who bounced immediately.

Not having a clear kill switch is dangerous. You need to know in advance what metrics mean you should pause or stop a campaign, not make emotional decisions when you're watching money drain away. I always set up rules, if CAC goes above X for more than three days, pause, if day-one retention drops below Y percent, pause, if cost per registration exceeds Z, pause. When working with influencer campaigns, having these clear performance thresholds becomes even more important since the costs can escalate quickly.

The apps that succeed with user acquisition are the ones that treat it like a science experiment rather than a magic trick, they form hypotheses, they test systematically, they track everything, they kill what doesn't work quickly, and they double down on what does work slowly and carefully.

Conclusion

Working out what to spend on getting new app users isn't about finding some magic number that works for everyone, it's about understanding your specific economics and testing your way to channels and costs that make sense for your business model. Start smaller than feels comfortable, learn faster than your competitors, and only scale when your numbers clearly tell you it's time.

The apps that win aren't always the ones with the biggest marketing budgets, they're the ones that figure out their unit economics early, find channels where they can acquire users profitably, and then scale methodically without panicking or burning through cash on vanity metrics. Your user acquisition cost should be a number you're constantly working to improve, not a fixed cost you just accept, and every pound you spend should be teaching you something about who your users are and where to find more of them.

If you're working on an app and need help thinking through your user acquisition strategy or building something that's actually ready for paid marketing, get in touch and we can talk about what makes sense for your specific situation.

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