It's true that you could potentially spend a lot on in-app purchases, so I have a personal strategy. As long as I'm getting entertainment and value from the game, I'll purchase the battle pass each season, which costs around $9 USD. This lets me to unlock a bunch of additional content by playing. I avoid the "deals" and "sales" they offer to prevent being continuously charged small amounts.
I don't think I've played anything but Marvel Snap since it came out. It's a turn based Marvel card battler, that also scratches the Hearthstone itch I get. Highly recommend!