Your favourite/most unusual money-making methods

"Stormkeep;c-16878470" wrote:
@irishluck1986 Have two (or more) frogs in your sims inventory and then just click one of them to select to breed. It'll give you a dialogue to pick which other frog to breed them with and a new frog will pop out.

The action does have a cooldown, so you can't spam it. If you opt to breed frogs and also want to get the collection complete, check Carl's guides site for his frog breeding info as well.