How to find the biggest cashback bonus for anything you buy

I've written many times before of my love for cashback services, which pay you back a percentage of your purchase just for going through their shopping portals.

For example, FatWallet recently started offering 3 percent back on Amazon Instant Video and MP3 purchases. And Ebates is currently paying 4 percent to 5 percent back on purchases from Dell, HP, and Lenovo.

Of course, there are lots of cashback sites out there, and some offer bigger bonuses than others. How can you make sure you're getting the maximum rebate for each store you visit?

Simple: click the Cashback Comparison bookmarklet. Provided by SavingCashback.com, this simple tool makes it a snap to see all the available rebates for any given store. (Don't like bookmarklets? You can also look up stores directly on the site.)

For example, suppose you're eyeballing some RAM modules at Newegg. Or a Blu-ray player at Target. Just click the bookmarklet and presto: You get a complete list of the cashback sites that support that store and their latest rebate percentages.

Once you've found the best deal, you can easily click through to that cashback site to start your shopping. Granted, all this adds a few extra clicks to your shopping experience, but if the return on that "investment" is 4 percent, 7 percent, even 9.5 percent, isn't that worth the effort? I certainly think so.

The bookmarklet is compatible with all browsers and requires no setup beyond simply dragging it to your favorites toolbar. And there's no setup or registration required at SavingCashback.com (though obviously you will need to register with any cashback sites you end up using).

By the way, that site has some other great money-saving tools as well, most notably an exhaustive list of discounted gift cards. It's definitely worth a look.

Have you found any other tricks of the cashback trade? A toolbar, perhaps? Share your tips in the comments.