Case · Mobile apps
6 months
Trial to paid from 11% to 17% by buying trials, not installs
A budgeting app paying for installs that never opened the app twice. We optimized to trial starts, fixed SKAN mapping and moved half the budget to TikTok.
Illustrative
Cost per install
−31%
€3.90
→
€2.70
Trial to paid
11% → 17%
11%
→
17%
Monthly installs
+2.4×
15.4k
→
36.9k
Illustrative demo figures for a fictional client. Results vary with margin, market, offer and spend.
01
Challenge
Coinlet is a budgeting app that splits bills and schedules payments before payday. It came to us spending €60k a month on Meta and Google App campaigns, at a €3.90 cost per install and 15.4k installs a month.
The install numbers looked healthy. The business didn’t. Only 40% of installs started the free trial, and just 11% of trials converted to paid, so each paying subscriber cost around €89. Campaigns optimized to installs, which taught the algorithms to find people who downloaded once and never came back.
iOS was worse. The SKAN conversion-value schema only counted app opens, so every postback looked the same and nobody could tell which campaigns started trials. Budget calls were made on Android data and applied to both platforms.
02
Strategy
Daan started with measurement. We rebuilt the SKAN schema around three events that predict revenue: trial start, first bill split and a second session within 48 hours. iOS and Android moved into separate campaigns with separate targets.
Next, we switched optimization from installs to trial starts through Coinlet’s MMP. Volume dipped for two weeks, then recovered as the algorithms found better users. Install-to-trial rose from 40% to 46%, and a day-three onboarding change that Coinlet’s product team shipped from our funnel data helped trial-to-paid climb.
Finally, we moved half the budget to TikTok, where rent-day and payday content already had an audience. Monthly spend grew from €60k to about €100k while cost per paid subscriber fell from roughly €89 to €35.
03
Creative approach
Budgeting ads usually sell calm and control. Coinlet’s users talked about specific, stressful days, so we built the creative around those moments.
The lead TikTok video opens on a rent reminder and the line “Rent day, sorted in two taps.” It shows a bill split and scheduled in under ten seconds, then ends on the install button. It became the cheapest source of trials in the account and drove most of the 31% drop in cost per install.
On Meta, a 1:1 static with the hook “Your coffee change, auto-saved.” sold round-ups and the 30-day free trial to people who don’t think of themselves as budgeters. Over six months we tested about 70 concepts across creator videos, screen recordings and statics, and rotated a fresh hook into every ad set each week.
Funnel
Where
the
extra
revenue
came
from.
Bar length uses a log scale so every stage stays readable. Illustrative demo data; results vary.
Results
The
numbers,
month
by
month.
Over six months, cost per install fell 31%, from €3.90 to €2.70. Trial to paid rose from 11% to 17%. Monthly installs grew 2.4×, from 15.4k to 36.9k.
The number Coinlet cares about most moved furthest: paid subscribers went from 677 to 2,887 a month, and cost per paid subscriber dropped from about €89 to €35. Store-visit-to-install rose from 30% to 38%, helped by new store screenshots that match the ads.
iOS campaigns now report trial starts through SKAN in enough detail to set budgets, and TikTok carries about half of the spend.
Illustrative demo figures; results vary.
Creative
The ads that did the work.
The ads from this account, as they ran. Videos play muted in view; open the creative library to hear them.
Open the creative library
Coinlet · ad
Result −31%
Coinlet · ad
Result 17%
Sam Okafor
Demo testimonial · fictional person
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