I have no idea if you over paid or not but I can say those don't come up every day. So given that you didn't pay a vast fortune for it and how much fun it will be I'd say you did just fine.
I'd go 3F on the powder since it's under .50. And you'll want to pick up a box of .440 balls and possibly a box of .445 balls and some patching material. I recently found a bag of 1000 100% cotton twill patches for cleaning that I'm hoping will do double duty as patches for the round ball. For that use I'll likely cut the corners off to turn them into octagonals. But hey! The price was good!
There's a number of potions you can use for lubricating the patch around the ball to reduce or avoid bad fouling. My own favourite is Ballistol mixed with water about 1:5. This makes a white milk like mix. I apply it by starting the patch and ball into the muzzle with the short starter. This leaves me with a frill of patch at the crown. I dribble on about 5 to 6 drops worth of the Ballistol milk then use the other end of the short starter to seat the ball a little deeper. The ram rod is then used to push the ball down and firmly tamp it against the powder.
NO AIR GAPS ALLOWED! ! ! ! So be sure it's all the way down and on the powder. Air gaps leads to detonation and big peaks in the pressure instead of a progressive burn with more of a push to the charge going off.
Cap shooters also remove the cap and clean out the flash path with pipe cleaners or the like. So get yourself a suitable nipple wrench while you're stocking up.
It all sounds like a lot of work when you read our replies. But it's really not as bad as it sounds.
Here's a list of things you need for the first range trip;
- A powder horn or powder flask to hold the powder.
- A measure to use for measuring the powder and transfering it to the barrel.
- .440 round ball
- Cotton patches for black powder shooting or some cotton twill pillow case ticking that is around .012 thick. (just buy the patches for now).
- Ballistol Universal oil for lubricating, protecting and mixing up the patch lube.
- A ball starter.
- Proper size percussion caps to fit your gun's nipple.
For cleaning at home get yourself a shot gun cleaning rod kit that has a "T" handle. Add to that a .45 caliber brush. Why the shotgun rod? That's so when you get the brush to the bottom of the bore you can give the handle a bit of a clockwise twist while pulling back. This will twist the bristles and let you draw the brush back. Otherwise they get stuck in the bore like a Chinese finger puzzle and you're left wondering what to do. With the shotgun rod you just give it a bit of a twist and pull back easily.
If your barrel has a reduced size powder chamber at the breech you'll want to find out what size it is and use the proper size brush for that. I've been wrapping a pipe cleaner around the end of pistol size brushes to convert the brush into an end and side cleaning brush instead of just a side cleaning style. Adapting stuff like this is just part of the fun of shooting blind ended bores like us BP folk do.
At first it'll seem like a lot of work. But with a few tricks like I've mentioned and what the others have suggested you'll have the end of day cleaning down to around 15 to 20 minutes from filthy to slicked up with fresh oil and ready to put to bed.