Lots of good muzzleloaders for sale today, new and used. My favorite was a Knight Wolverine I bought from Blaster but its been passed on to other family. Doesn't need to be a high dollar gun to get excellent performance. I've always shot TCs and the Omega is a great gun for the money. CVA and Knight make good guns too.
As far as scopes a good 3x9 or 4x12 is what we've shot and liked. Then it depends on how much money you want to spend. I've got a Bushnell Banner 4x12 and it was around $100, great clear scope, really happy with it.
I second what JNRBRONC said about the new Blackhorn 209 powder. It makes muzzleloading easy and lot less time consuming. No worries about self life of your powder, cleaning between x amount of shots at the range, etc. Try a few different grain loads with your bullet of choice (we found 110 grains to work the best). Also when shooting this powder make sure to shoot a stronger primer, primers made for muzzleloaders won't do. Something like a CCI or CCI magnum that are made for reloading will burn hot enough for the powder.
Also when looking at bullets the most common ones are Knight/Barnes, Hornady/TC, and Powerbelt. We prefer the Barnes/Knights Spitfire TMZs, a saboted bullet with polymer tip, solid copper for 100% weight retention, and boattail for increased accuracy. Good luck, you'll be tapping into some good hunting during the muzzy seasons!