Board Thread:Plants vs. Zombies Wiki discussions/@comment-36483640-20190612051502/@comment-37054964-20190613013623

50 coins every time you complete a level. 10 coins for every lawnmower you have remaining at the end of each level (up to 50 coins every level). And a random amount that you can get just by beating zombies, it's more likely that thay'll give you coins on higher levels, I believe.