This deal has ended.
Through 4/30, Restaurant.com takes 80% off all their dining certificates via code MEAL. This lowers the price on $10 certificates, which are normally $4, to $0.80 and $25 certificates, normally $10, to just $2. Obviously, not all restaurants participate, but there is definitely a good selection to choose from. Just be careful to read the fine print as many restaurants exclude alcoholic beverages, weekends and other things.