This page will list a few ways of making money within the game.
Begging Bowling Casino Referals Trading
Begging is the main money maker in the game, based on your intelligence and begging skill this will start off making very small amounts of cash but as you level, train and beg more the rewards will be greater
Bowling is one of the newer features braught to the game in the second city, you will have to pay an initial 1000 cans to get some bowling shoes, but from then on you can use 15 awake to play a game.
My first time I played I bet $100 and made $6000, so it is quite profitable. - PrivateSniper
The casino is obviously a bit hit and miss, but offers three games in which you can "win big".
Easy enough, you send your friends an e-mail or give them the link - You will get $500 straight away and $5,200 extra once they turn level 10