Here's another YMMV but it happened for me... because the clerk did a manual override on the 50% coupon, it was still sitting in my active offers a couple days later. Check your active offers on the PUR site and if your coupon is still in there it could potentially be printed out and used again.
The website appears to be restocking from time to time... some decent stuff on there now including Mario Power Tennis, Hulk: Ultimate Destruction, Simpsons Hit & Run, Ultimate Spiderman, and some Need For Speed games.