what are the best things to do with extra income?
1st choice - use it to pay down any debt.
2nd choice - if you don't have any debt, you might want to consider adding it to your Emergency Fund.
3rd choice - If your emergency fund is already taken care of, you might want to add it to one of your savings goals.
4th choice - If all this is taken care of, go and spend the rest for a little treat :-).