Restaurant.com gift certificates: 90% off

Restaurant.com is selling its gift certificates for 90% off (use code NINETY). That means that a $25 gift certificate costs $1 and a $50 one, $2. There is usually a minimum purchase, about $35-$50 for a $25 GC and $100 for a $50 GC.
I’ve used restaurant.com gift certificates several times now, and I’ve not have any problems with them.