There are MANY radio stations all over the country that offer "Half-Off" Gift Certificates to local places and events. Basically, you buy a $50 Gift Card for $25. (some stipulations usually apply) The stations will offer these every week so you have to keep checking back to see when the deal starts. They are usually limited so it's "first come, first serve."
I have done this twice at my local station that offers this, WINK 104 (Harrisburg, PA), and have been VERY happy with the results!
Here is a list of what I, and others, have found: (Listed Alphabetically)
Atlanta - V-103
AtlantaHalfOff: Atlanta Half Off
Boston - Mix 98.5
Mix 98.5 Today's Best Variety - 50 50 Deals
Chicago - B96
ChicagoHalfOff: Chicago Half Off
Dallas - Mix 102.9
Half Price Hook-Ups: Home
Denver - Alice 105.9
About.com: http://www.alice1059.com/
Detroit - (station ?)
GMD: Motor City Steals & Deals
Gainesville/Ocala (Florida) - 98.5 KTK (SKY 97.3 also has a link to the same site)
98.5 KTK
Harrisburg (Pennsylavania) - WINK 104 (click on "Half Price Harrisburg")
WINK 104 WNNK-FM, Harrisburg PA Radio Stations
Long Island (NY) - (station ?)
Long Island Radio Discounts: Home
Miami - 93.7 The Coast
About.com: http://coastfm.com/
Philadelphia - 98.1 WOGL, click on "Half Off Deals" at the top of the screen
98.1 WOGL - Philadelphia - Homepage
Phoenix - 99.9 KEZ "Beth and Bill's Big Deals"
Beth and Bill's Big Deals: Home
Pittsburgh - 93.7 B94
WBZW: Discount Market Place
Virginia Beach - Z104
WNVZ2 - Norfolk, VA - Hampton Roads Perks
Washington D.C. - 98.7 WMZQ
Half-Off DC:
If you are looking in YOUR local area: I have found that most of the sites that contain these deals, tend to be the radio station that either play "today's hits" or "adult contemporary" music.
If you find a station, please list it and the link! I will be updating this list every so often! (Even the smaller cities offer these deals!)