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Since i cannot see the radiographs, I cannot say whether or nor surgery is the best or only option, however if you cannot afford to have the fracture surgically repaired, you can always try to have it splinted and hope for the best. This requires bandage changes and recheck radiographs in the future and although not ideal, may work out for him. However if the fracture does not heal properly, then amputation would be your only option at that point.
If you do not want to wait to see how he heals, you can talk to your veterinarian about amputation. It is sometimes less expensive than repairing a fracture and although it does not result in a functional limb, dogs do quite well with 3 legs, especially when they are young. I myself have a three legged dog and people are often surprised to learn that he only has three legs after watching him run around and play.