I just found that Ebates is offering a coupon code for 5% off Groupon.com. I constantly search for Groupon coupons and have recently landed on this gem of a coupon for 5% off any and all of your Groupon purchases. Also, this coupon is unlimited in that you can use it as many times as you want. Check out the link on the bottom for Ebates' information page. Unfortunately, Groupon doesn't allow people to post links to non-Groupon sites on Guides or Reviews. However, I put the link for Ebates on My Groupon Page (which is what the link below will bring you to). Since this is a guide, I will go over some of the info I learned about Ebates, otherwise you can skip to the bottom to find out for yourself.
From my research, I found that Groupon has recently hired Ebates to promote sales during the recession. Every time you buy something on Groupon, you get refunded 5% of what you paid for it. The way this works is that Groupon pays Ebates a commission each time someone uses Ebates to buy something on Groupon.com. In turn, Ebates pays you part of that comission (which is how they give you the 5%). This way, everyone makes out (including Groupon). Ebates has also negotiated similar coupons with over 1600 popular online stores Examples of other coupons include 1 800 Flowers (10% off), ProFlowers (16% off), FDT (20% off), TurboTax (7.5% off), Kohl's (6% off), Sears (5% off) , JC Penney (8% off), Drugstore.com (6% off), Neiman Marcus (8% off), Nordstrom (5% off), DSW (4% off), Macy's (6% off), Sears (5% off), K Mart (6% off), Overstock.com (2.5% off), Home Depot (3% off), Walmart (1% off), Target (2% off), Half.com (4% off), Travelocity (5% off), Orbits (5% off), Staples (6% off), Best Buy (1.5% off) etc. Note that these percentages often changes, so they may be higher or lower depending on what the current offer is.
Again, these coupons can be used an unlimited amount of times (making this better than a typical coupon code you get in the mail). This can be used for any item and any category on Groupon.com. There is also no restriction to how expensive the item if for. I hope this spreads the word! Can't go wrong with free money in your pocket.