I recently made a purchase an off the floor pet cot on Groupon. The price didn't seem unreasonable, and there was a $10 off promo code available that I applied to the purchase. That was the thing that really made me decide to buy it. The first electronic invoice showed the $10 taken off. Cool! The final invoice and my PayPal account showed the full amount was charged. Groupon customer service was of no help. They said some items are restricted to the promotions. OK, I get that. But why did it show the money taken off the total at first then pull it back in? No explanation. There should be a system that alerts the buyer that the promo code is not available for some items before the actual purchase. The item has already shipped even before they got back in touch with me.