Restaurant.com has a new 90% off coupon code JOY available. The $25 discount certificates are normally $10 or $15 (depending on restaurant), but are $1 or $1.50 with the code. They also sell $10 certificates for select restaurants for $5, making them $0.50 each with the code.
Restaurant.com is offering 70% off Dining Certificates via coupon code PREZ through 02/19. $25 certificate is on sale for $10 - 70% off = $3. Please read the minimum spending limits for each "gift certificate" and other restrictions before you purchase.