Free Money
Once you have built the "Vault". Go into to it. ( If you dont know where it is, it is in the basement, down the stairs on your right. It is NOT a door..its more like a round metal bump sticking out). Once you get in. There is a machine (It had $ on it and I think its brown?). Go on up to it and make money. You get 100$ each time i think..or 10$.