Have you purchased a copy of "Home Power" magazine or read it at your library if available?
Peruse the ads and you will find that there are some reasonable ones advertised.
Reasonable of course is determined by each individual. Cost per KWH would be how I would judge reasonable.
One of the cheaper models does have more blade noise with it than some of the others. Take that into consideration before making a purchase.
Target stores were a wind generator/charger franchisee for awhile. You might check with a Target store near you. I don't know if they are still carrying the units or not.
While the generator/charger is fairly inexpensive, the tower, installation, and controls are a bigger cost. Also batteries to properly utilize the power produced.
If you wish to home build a unit, the Savonious rotor style looks relatively simple to construct. I now have access to free poly barrels so may give one a try. I also bought a salvage auto so have an alternator to play around with.