Well I'm In Canada... don't know if that makes much difference... but my car has the Exhaust Manifold with the built on Catalytic Converter all in one piece. So here's my options:

Used from a junkyard $250 (probably sell mine for $80 back to them)
New Aftermarket $300

Have it removed and taken to a welding shop, I'm not sure what the mechanic would charge to take it off and put it back on... but the welding would be $80.