PriceProtectr.com actually does what you always mean to do: It monitors when your wish list items—or purchases you've recently made—go on sale. Just copy and paste the URL of the item onto the site and you'll get an e-mail when the price changes.
Groupon.com negotiates one local group deal per day in more than 60 locations across the country—say, half off Bollywood dance classes or a free entrée at a popular restaurant. As long as enough people sign up, the deal is on. Register for the site's local e-mail blast and you'll get daily missives inviting you to join hundreds (if not thousands) of strangers to leverage your collective bargaining power.
TheDealMap.com aggregates bargains from sites all around the Web. Just type in your zip code, choose the category of deal you want (such as "events and attractions," "hotels," or "home and garden"), and up pops a map of your area with the locations and details of each coupon or sale.
eBates.com snags you 4 to 7 percent cash back on online purchases at thousands of retailer links on the site, from World Market to Home Depot to BlueFly. Just go to eBates, and click on the online shop you want to visit. The site will receive a fee for referring you. They also split the fee with you, so you get a check in the mail along with your new blender or sandals.