Starting tomorrow 12:01 AM CST, Groupon is offering $10 GC for $5
DEAL IS DEAD
Looks like it is active for some groupon members. I received a targeted email saying its active and was able to purchase it.
Only one per credit/debit card. If you are having legitimate problems (i.e. two different accounts with two debit cards using the same billing address), opening a different browser (IE, Chrome, FF) should work for you