Many anglers wonder what the difference is between spinning reels. In all honesty there isn't a ton of difference, and there are many quality spinning reels available for very affordable prices. As a matter of fact, for ultra light to light action fishing (which are the sizes that offer the most "sport" to your fishing experience) it's probably not necessary to spend any more than $50 for a quality spinning reel. Some manufactures that produce quality spinning reels would include: Daiwa, Pflueger, Quantum, and Shimano. My personal favorite id Pflueger, but this is simply my personal preference.
The biggest single factor in picking out a good spinning reel is the amount of ball bearings that are in the drive mechanism (which is where the handle is turned). Generally the more ball bearings, the better. Why is this? Simply because the less ball bearings there are, the more "play" there is in the crank, and the less play there is, the better. I personally like having very little or no "play" in the handle of my spinning reel. To me, this play factor is the biggest single factor in a good spinning reel.
After this what your looking for are mainly ascetics. After all, you want your reel to look good with the rod your using, right? Not only look good but fit properly. This is usually fairly simple. If you have an ultra light action rod, buy an ultra light reel, and if you have a light action rod buy a light action spinning reel. This information can be found in small print at the base of your fishing rod, in case you didn't know.
Another consideration, that is again up to personal preference, is the location of the drag adjustment. The drag adjustment will be either on the spool or heel end of the spinning reel, and is a consideration. I prefer my drag adjustment be on the spool end, but again this is largely up to personal preference. My fishing buddy prefers his on the heel of his spinning reel.
The bottom line is that any of the manufactures mentioned in this article would be a fine choice for a good spinning reel. Problems usually arise when anglers buy from un-known manufacturers or try to be too frugal. I would personally be really wary of any spinning reel that cost less than $20. However for $25-50 you should be able to find a really good spinning reel.