When browsing a listing in the App Store, I always used to jump immediately to the in-app purchases section and pattern-match for two things: “1 month, 3 months, 1 year…” in the case of apps, or “10 gems, 50 gems, 150 gems…” in the case of games. Either would be an instant disqualification.
I say “used to” as I gave up browsing the App Store.