A USGI bolt will probably run about $150 from the usual sources. Keep an eye out on some of the milityary rifle forums for a good used one that is in spec. The cheapest I have seen was from SARCO and they were $79 but they were aftermarket. Go to the
CMP Forum, then register and ask if anyone has a new one for sale.
You could put a WTB post in the appropriate gunshow sub forum and see what happens.