I bought 2 groupons. I own a remodeling business. The first time i went there they chatted me up about their products and abilities, but then they did a poor job of color matching a paint sample. I used the paint anyway. When i went back to buy more product they made excuses about the color match--blaming me and the sample i brought. I had another color match project with a very large, clear sample chip. Their first attempt didn't match the sample this time either. After I insisted it was not right they manually add tint until they got it close.
Two complaints--they were unsympathetic about their inability to accurately match my color samples--no offer to redo the first bad match and reluctantly adjusted the second mis-match. And secondly they declared the Groupon could not be used against contractor pricing. I think most businesses consider the Groupon as a loss leader to attracted customers who might not ordinarily buy from them in hopes of expanding their customer base. It didn't work with me. In fact they totally turned my off from going back. A misuse of the Groupon and a missed opportunity for them.