This is what I use, and it's only $9.99
http://www.talkietech.com/touchprocase-3986.htmlthe plastic case fits pretty well over the phone, and includes a swiveling belt clip that attaches to the back of the case. the overall quality is average, but a good value for $9.99. the only problem is that if you need to take the case off and on a lot (for example using two batteries or micro sdhc cards and swapping them out) there's no reall good way of taking off the back cover without pulling on the slid mechanism, which is now a bit wiggly but still not really damaged.
talkie tech's customer service was excellent, I might add. I ordered this case, a spare battery, a cradle and some accesories for my wife's Samsung Rant. they shipped everything but the cradle as the cradle was on back order, so I emailed them and asked if they would ship the case later when it got into stock with free shipping as that was the whole reason why I purchased from them (another website had everything but the cradle at a slightly lower price but I wanted to save on shipping) they replied that they searched the warehouse and found a cradle, which they they shipped free. I ended up getting both packages the same day just a couple of days later. also if you google "talkie tech coupon code" you can get 15% off, or free shipping (which i think you get anyway if the order is over $50).
Anyhow, I don't mean to be a shill for talkietech.com, but I was really impressed with the value and customer service.