Web site Restaurant.com sells gift certificates to participating restaurants all over the country, often offering deeply discounted prices. Right now the site is selling $25 gift certificates for $10, which isn't a bad start, but from now until Halloween, entering TREATS at the checkout applies a second 80% discount to the sales price. The result is a supremely cheap $25 gift card for just $2. Want to aim higher? The same discount applies to more expensive gift cards as well, so you can snag a