There are bound to be some feed stores (probably a locally-owned one) which either carries or can get good quality, American-made wire. Go with 14-gauge 1/2" X 1" galvanized-after-weld (GAW) wire for flooring, and either 16-gauge or 14-gauge GAW wire for the sides and top. The 14-gauge tends to be more rigid and durable, but it will pay huge dividends in how less frequently it wears out.
My personal preference is to order the cages pre-cut, then assemble them myself when it gets here. In the long run, it doesn't wind up costing me any less to buy big rolls of wire, cage accessories, etc., (with shipping costs being what they are), and doing it myself from start to finish as compared to buying them pre-cut, and I sure don't miss the sore hands, wrists, and blisters.