Decide what you want to spend on one (don't forget that you'll need a scope and mounts,
\\This assumes you prefer one of the "inline" contraptions, and/or have an aversion to using open or aperture sights. ALL muzzleloaders are fun, but the funnest of them all are the flintlocks. There are a lot of nice flinters, but if you start out with the Lyman Plains rifle flintlock, you're in the right vicinity.