Yup, like bubba say's Track is just one that will do the labor for ya but it can get quite involved when starting with a rifled blank. Track has their costs listed and their not out of line compared to just about anywhere.
http://www.trackofthewolf.com/Categories/PartList.aspx?catID=15&subID=86&styleID=306
FWIW, they don't do the work at their shop. They have a contract smith. They ship out, then get it shipped back to them, then it goes back to you.
Let's see; install breech plug, cut sight dovetails, cut underlug dovetail, drill an tap for under-rail, or solder under-rail and thimbles,, :hmm: ,,that's about it.
So it's about $140-> just for labor,, then ya gotta buy the parts and pay for shipping.
That's why those premade drop in barrels are so high, it's actually a savings when ya put it all together because they mass produce'm.
Alot of guy's do some if not all the stuff themselves. It's a good idea to have the barrel breeched by a pro with a lathe and experiance but the rest is fairly easy if a feller is handy with basic tools.