Groupon offers a $25 Credit for Big Skinny Wallets for $12. That's a $13 savings and tied with our June mention as the best offer we've seen from this merchant. Big Skinny specializes in ultra-thin wallets that purport to be up to ten times slimmer and five times lighter than traditional wallets. The voucher does not include shipping costs, which start at $3.45. Limit three per person. Credit expires December 22.