If you want to shoot any heavies out of it, look for a 1-9. Most 22-250's have a 12 or 14 twist and don't handle the heavy bullets well.
For barrels there are plenty of different makers out there. Most will turn a factory Rem contour if that is what you want. Kreiger, Hart, PacNor, Lilja, McGowen, Douglas are a few places to start your search.
Most 'smiths will charge $125-150 to thread and chamber a barrel. There is no reason it should cost any more than that to have one installed.