Never used one, but my sister paid £19 odd monies recently at an attempt to get her boyfriend beefed up.. results pending.
If you're looking for one, at this price maybe worth a pop (shock?)
Reviews seem ok
The ABGymnic Muscle Toning Belt works by stimulating your muscles with small amounts of electrical current. Now you can exercise wherever you are, whether at work or relaxing in your living room! The ABGymnic wraps around your abdomen, arms, legs or buttocks. While it stimulates your muscles, you will only feel a tingling sensation - imagine getting a full workout and only feeling a slight vibration!