For the second time now, I have had a valid coupon rejected in the marketplace.   The coupon expires at midnight, CST.   I copied the number from the e-mail and pasted it into the relevant field at the checkout.   It was only when I finalised the purchase that I was told that the coupon was invalid, or expired (neither true).   When I tried to re-run the operation, I found that the items I was trying to buy were already in my list of purchases;  the purchase engine had disregarded my coupon, but validated everything else.   In other words, regardless of the coupon to which I was supposed to be entitled, I had paid the full price for the things I had bought.

Hi Morgano,

Did you hit the "Apply" button after entering the coupon code, before completing the checkout process?

Thanks for replying.   I am not certain about the "Apply" button, but I think that I must have used it, because the checkout process did detect the coupon and explicitly (and invalidly) reject it.  

I'm going to email you shortly :)