That depends on the material. Those made of sand-cast aluminum are repairable at about 1/3 to 1/2 the new propeller price. Die-Cast propellers generally are not repairable. The material is very brittle, breaks off easily in the straightening process and will not weld satisfactorily. (Original equipment propellers are usually made of die-cast). It is advisable to discard such propellers and replace with the more durable sand-cast aluminum.
Authorized propeller repair stations located across the country offer extensive service.