Priceprotectr.com helps you get money back if items you bought have dropped in price. Register your purchases, and e-mails will arrive when the prices have fallen. Claim the cash with an e-mail, phone call, or store visit.

Gasbuddy.com and gaspricewatch.com track the cheapest gas stations by area. Plug in your destination to find the best places for filling up.

Retailmenot.com amasses coupon codes for discounts at 15,000 online merchants. After you enter the e-tailer’s Web address, you will get a code to receive your price break. Go mobile with cellfire.com, a site that lets you access coupons on your cell phone. Then you show the code on your tiny screen when you are at checkout.

Thegrocerygame.com (cost: $10 for two months) provides a weekly list of the lowest-priced products at your favorite supermarket, matched up with manufacturers’ coupons and specials to save even more. You can pay extra to sign up for multiple grocery stores.

Honesty.com lets you know how much things usually go for on eBay and what’s currently for sale there, so you don’t overpay when you buy. Type in an item name for price comparisons on current and recent eBay listings.

Pricespider.com and wishradar.com hunt online for the items you want at the most you’re willing to pay. Create a wish list and the most you’d spend for each purchase. Then the sites search for the products, e-mailing you when they turn up your desired price — or less.

Bookingbuddy.com consolidates many travel sites to get you low airfares, hotels, car rentals, and vacation packages with a targeted search. Enter details of your trip once, and then click on the names of the Websites you want Bookingbuddy to search — from Expedia to Priceline.

Goodhousekeepingrewards.com lets you earn cash-back rewards of up to 20 percent at over 200 participating online merchants including Wal-Mart, Gap, Sephora, and Best Buy. Membership is free to subscribers and comes with a 90-day trial period for nonsubscribers.

By Kelli B. Grant – goodhousekeeping.com