Ok, so i've been wondering how Steven gets his money with his dad only working a carwash, and of course Greg got his Big Bundle o' Money, but I still wondered how Steven and his dad got by, having 3 mouths to feed (including Amethyst, that is.) but NOW i have an answer!
Amethyst (and later Steven as well) would win money in their underground tounaments! I also think that one of the reasons they decided to quit wrestling is because they didnt need to because they could get all the money they needed from Greg.
Unless someone can disproove this somehow, I now have the answer to the question that's been bugging me since the begining!