New or used Leupold VX-1 2x7x33 or 3x9x40. Both will come with a lifetime no bs warranty.

Others would be Nikon Prostaff or Buckmaster, Burris Fullfield II.

Check out for style and price comparisions (scads of other online sites as well, but the folks at midsouth are top shelf):
www.midsouthshooterssupply.com

If the base and rings are good then you can get a nice scope in the $150-300 window. As always, I recommend to get the best optics you can afford. You will not regret quality optics.

Does not have to be a "muzzleloader" scope (marketing fluff for the most part). Any quality riflescope.

Tahquamenon