What's the ballpark to fix an exhaust on a car with a catalytic converter?

What is your question?

To start off, the car I'm asking about is not a Plymouth Acclaim. It's a 1988 Plymouth Horizon, they just didn't give that option when I started. So, I'm looking to buy this car, but it doesn't have any plates on it, so we can't drive it the hour plus to our mechanic with no plates, and he's way too busy to come out and look at it. The exhaust is LOUD and the guy trying to sell it to us says that the exhaust pipe has a leak in it. The car has a catalytic converter, so we figure it would be more expensive than if it didn't, but we still don't know about what it would cost. I'll probably call my mechanic at some point and ask a ballpark of him too, but I just want to know about what it looks like, given that I'll probably have to buy the car before it sees our mechanic.