Thompson Center Black Diamond XR

I'm looking for information on a Thompson Center Black Diamond XR. It's a .50 cal, with the stainless barrel and synthetic stock. The one I am looking at is used, about 3 years old, and in good shape.

I've never owned a muzzleloader, so would this make for a good "first"? What would be a good price for this baby?

Thanks for your help!

First thing I'd do would be to check the condition of the bore. If it's bright and shiny with no pits (Stainless can and will pit) and the rest of the gun is in decent condition, maybe 150 bucks. Does it have 209 ignition? If the answer is yes, check the breech plug where the primer sits. Is it gas cut? Is the face that the primer seats on all chewed up? These are important factors, and help in telling how much the gun was shot. The Black Diamond is an excellent first muzzleloader, BTW.