Just for the heck of it, and because I seem to be out of fresh ideas at the moment, I'm trying the millionaire scenario. I always build my own houses, so I started with a pre-made house so that when ...
One more money-making tip - collect a couple of rare frogs, or breed one from a pair on non-rare frogs, and then breed them together every four hours. Each one is worth $125, so you can pick up $750/day.