Intake and Exhaust Manifold Cost

My Dart is missing one of the exhaust manifold studs. As my mechanic was inspecting it to repair, he noticed that my exhaust manifold has a crack in it. (I guess that explains the exhaust leak)

He told me to look for an intake and exhaust manifold pair, if possible. The questions:

1. How much should I be paying for these parts? Ebay isn't always the best gauge if you don't really know what you're looking for.

2. Since I just spent all my coin doing brake and suspension rebuilt, anybody have an intake and exhaust manifold they want to part with on the cheap?

Anyways, if you could let me know what I should be looking to pay, that would be very helpful.