Credit Card Rewards Programs.
Proceed with caution with this one. You have to be able to pay your balance 100% of the time ON TIME or you earn nothing.
However, if you can do that, if you can pay the bill and reap the rewards, do it! Try paying monthly bills like your phone, internet, etc. through your credit card. That way you can immediately make a payment for the exact amount and you save that cost of a stamp (this goes hand in hand with the save the stamp money tip here).
We have graduated to charging all kinds of things, from gas and dinners out to bills and vacations. However, I also have enough in my savings account to make sure I can cover any bill if for some reason I overcharge. This one is one I really urge caution with, but you can reap excellent benefits if you play it right!
Try putting the cash back rewards directly in to your savings account. Say you earn $20 a month, that's $240 of free money directly in to your savings. Not shabby at all.