I called Groupon to complain after attempting to redeem my certificate of $0 for $20 and was denied..was told that they make only $5 off the deal.. not my concern.. and had to coerce to get my original outlay of $20. Feel that they use Groupon as a marketing vehicle.. also noted (after 3 other comparisons) that they charge almost double on some items... bait and switch.. now obligated to at least spend the $20 outlay there. They said that 2 others had tried to redeem as well.