I'm making an assumption, but if you are looking for a rifle for expense of cost and ammunition, and want to shoot a lot, then a muzzleloader is not what you want. They are every bit as expensive per shot, and a lot more trouble to clean, than a good old .308 rifle.
If you are buying the rifle for the extra deer season, then they are a good choice, but a .308 can be had for pretty much the same price, and the ammunition is readily available about every where you go, for a fairly decent price.
I own several ML's and they range in price from $250.00 w/o scope to $600.00 w/o scope. If you use a sobot and good grade of bullet, you are looking at between $.75 and $1.50 per shot according on the powder, primer, and load combination your rifle likes to shoot. All of them will shoot good groups at 100 yards. 1" groups are not uncommon with the newer inlines.