Repo duster fenders
AAR Quality Fiberglass has glass fenders, but nobody would call them cheap. 345 clams to be exact. check out their stuff at
www.aarqualityfiberglass.com
If a little of the fender is messed up then you can just buy a patch panel and save a ton of money. Of course, if the whole thing is trashed you should probably go to junkyards and search ebay for a while as the fiberglass ones are really not necessary and super expensive. There's probably someone out there with a better solution so, we'll see!