Well, let's see. If you go to Jack's Powder Keg (
http://www.jackspowderkeg.com/) you can get a case of 25 lbs. of GOEX for $14 a pound shipped to your door. I do that every year or two.
Shooting 95 grain loads in just about all of my guns, sidelocks and in-lines, I'll get at least 70 shots from a pound of powder. That's twenty cents a shot for powder.
For the sidelocks add another nickel for a #11 cap, round balls I cast myself from lead a roofer buddy gives me, a few ounces of olive oil from the pantry, and a yard of pillow tick for patching, and I'm shooting for something around thirthy cents or less a shot. That's $15 fro a 50 shot range session.
For the in-lines, add a nickle for the 209 primer, fifteen cents for the sabot, and forty cents for a Deep Curl, and (after including shipping & handling for sabots and bullets) I'm burning nearly buck with each shot.
I shoot sidelocks a lot.