There's adds after every level, almost all upgrades for the stores are behind adds and the ones that arent are super expensive for how little money you make. The only way to reliably make money in game is to watch an add after every level to apply a random multipler or to get special items in the shop to have a passive multipler added to every level which again, is behind adds or too expensive with how little you make. for some reason my game doesn't have soun too even though I have it enabled