In Bust Out Mode, if you have made a contribution to the value of the house of the Sim you are staying with, when you move away you will be reimbursed for it. Take advantage of this. Buy something expensive, move away, get reimbursed (automatically), move back and use the Sim Object as if you paid for it. Be careful, if you are in debt when you move away you will have to cough up some Simoleons yourself.