- www.upromise.com - this site rewards you primarily for online shopping. It used to be solely based on proving you cash back to invest in a 529 plan through a brokerage like Vanguard, but they have really expanded since I first joined in 2003. They now allow you to put your earnings in a high yield savings account, a 529, pay off Sallie Mae loans, or just get a check every 3 months. They have a pretty extensive list of online retail partners and they offer even more opportunities to save: through their credit card - which pays 1% cash back on every purchase, filling up on gas at Exxon or Mobil, dining out at specific restaurants, grocery store coupons, travel and the list goes on and on. I have saved over $1300 through this site. Granted that's over about 7 years, but I haven't spent a dime of money I wouldn't otherwise. All I do when I want to buy something online is go through Upromise first and it links me to the site and I save anywhere from 1-25%!
- www.bondrewards.com - this is a newer site that is similar to others in that you get rewarded for shopping online through their retail partners. The only difference with Bond Rewards is they pay you US Savings Bonds when you reach certain point levels. They don't have as many partners, but they do have a nice feature in which every email you get from them, if you click on it you earn points to more rewards.
- www.mypoints.com - this one is very popular and most people have heard of. It combines the shopping aspect, with lots of other ways to earn points, from ad clicking, email clicking, surveys, website registrations, you name it. They also allow you to get gift cards to a lot of their reward partners like Starbucks, Bass Pro Shop, Amazon, etc.
I don't ever recommend wasting time online, but hey, if you're going to shop online, you might as well be rewarded with free money for doing so! Or, if my wife and I go out to eat and spend $50 at a restaurant, sometimes I get $4-5 back just for going to one that is partners with some of these sites.
Seems like a Simple-Saving-No-Brainer to me...