Get a portion of the money you spend returned when you make qualifying purchases from eligible retailers. By Cameron Huddleston, Former Online Editor September 2, 2014 When you shop online, don't limit your money-saving efforts to coupon codes, deal alerts and price comparisons. You can also benefit from cash-back sites that let you earn back a percentage of the money you spend on qualifying purchases. SEE ALSO: 15 Web Sites for Finding Deals Online Here's how it works: You register with a cash-back site typically by providing an email address and creating a password. Any time you want to shop, sign in and then click on a store from the site’s list of retail partners. If you buy something, the cash-back site gets paid a commission by the retailer. The site then shares a percentage of that commission, in the form of cash back, with you. The amount you can earn back will vary from site to site and even from retailer to retailer. So it pays to compare cash-back rates offered by various sites to see which one provides the highest payback. Be sure to stick with cash-back sites that offer free membership. Here are five that we like. BeFrugal.com has more than 4,000 retail partners that offer cash back on purchases. The cash-back rates vary by retailer, but shoppers who create an account with the site earn an average of 7% of their purchase total, says Jon Lal, CEO and founder of BeFrugal.com. Once you’ve earned $25 worth of cash-back rewards, you can be paid by check or PayPal. Cash-back offers also can be combined with coupon codes and deals available on the site – so you save even more money. You also can earn $5 when you refer a friend who signs up for a BeFrugal.com account and makes $25 in cash-back-eligible purchases. Advertisement Coupon Cactus, as the name suggests, provides coupon codes as well as cash-back offers from more than 4,000 merchants. It pays cash back by check or PayPal each quarter if you have at least $10 in your account. You also can earn a 25% bonus of all cash back earned by others you refer to the site. Ebates has been around since 1998 and offers members cash back from more than online 1,700 retailers. Rebates vary by store, but many offer at least 5% back on purchases. Ebates pays cash back each quarter by check or PayPal -- or you can have the money donated to your favorite charity. It adds $5 to your account for each friend you refer who joins Ebates and makes a purchase of more than $25. Extrabux combines comparison shopping with online coupons and cash back from 2,500 online retailers. The site helps you find the best deal on a product by displaying prices and shipping charges from various retailers, plus cash-back offers and coupon codes. Basically, it puts all the available discounts on a product in front of you. Members receive cash back by check, credit card, Alipay or PayPal once they have earned at least $10, or they can opt to have the money donated to a charity. FatWallet highlights on its homepage the best deals its staff can find each day along with coupon codes and special offers from more than 1,000 retailers and cash back ranging from 1% to 40% from hundreds of merchants. Many of the retailers that FatWallet partners with occasionally increase their cash-back rates during what are called cash-back sales, and each day a featured store offers double its regular cash-back rate. Unlike the other sites, you can get paid by check or PayPal any time you want (amounts less than $10 can only be transferred via PayPal).