You can go to the bike shop and ask them for a replacement level wheel set. The stuff most shops have on display are of a much higher level (lighterweight, dual walled, aero spokes, maybe some needless bells and whistles). Depending on the shop and thier supplier, you can get them for anywhere from $20-40 each wheel. A steel set will even be cheaper. I just bought an alloy replacement rear wheel for my Bridgestone for $22 from my LBS.