Don't necessarily rule out a sidelock, either percussion or flintlock, although a percussion rifle will be cheaper of the two. Check a Lyman Trade Rifle or try to find a used T/C Hawken. Some Walmarts have the CVA Bobcat for $60 new. The bobcat is how I got my start in ML, but I found it mroe frustrating than rewarding, but others havd had better success with it. If you PM me I know of a couple of sources for used T/C Hawkens. These things are a ton of fun to shoot.