Is this similar to what your looking at? This is a picture of a repro 19th century screw on barrel boot pistol.
I'm imagining I have to determine the powder charge (how???), add a patch(lube?), ball, mash it all down, and add a primer (how does it stay in place?). The pistols I'm looking at are .36 cal.
You would measure out the black powder charge with a powder flask. They sell them at Civil War re-enacting sutlers. This is one Sutler that sells the powder flask
http://fcsutler.com/fcfirearmaccessories.asp. Scroll down to the end of the page. The one you want to look at is the Tubular Brass powder flask WITH spout. Make sure you get the right size measuring spout to go with the flask. If your using a musket you'll want a 60 grain spout for a .36 cal pistol you'll want the 15 grain spout. You can also look at The Regimental Quatermaster in Gettysburg PA.They have alot of gun supplies for black powder muskets and pistols. Everything I'm about to write is assuming the gun you might get is similar to the picture I posted above. My guess is you would have to use a .010 or .015 patch. For a percussion cap pistol the caps are made to snuggly fit onto the nipple. They should stay on once you place them on to the nipple. They're not perfect though and sometimes they fall off. If thats the case give the caps a little squeeze befor placing them on the nipple and they should fit tighter.
I'm looking at this as a potential hobby, and an alternative to my regular range time, as I need to conserve ammo. Does getting started have to be expensive? What is the bare minimum I need as far as gear?
It shouldn't be too bad but I guess that opinion depends on the person. To me what your looking at is pretty cheap compared to what I spent to get into Civil War re-enacting and black powder shooting. I've spent over 1,000 dollars in gear for my uniform, musket, and all the leather gear. As far as gear goes besides the gun the things you should look at getting is:
1) a Pistol cleaning kit (at the Civil War site above they sell the whole kit for about $18) Again you can also look at Regimental Quatermaster and Dixie Gun Works.
2) Pistol nipple wrench
3) Hoppes #9 gun oil
4) Spray can of ballistol
5) Cans of black powder
6) Percussion caps
7) Powder flask with correct size spout
Thats all I can think of right now if I think of more I'll post them.
One last thought, I was at a range with my EBR, and a guy shows up with a "modern" muzzleloader rifle and a buddy. The guy was sighting in for deer season, I assume. Anyway, he'd squeeze off a couple of shots, and then (I assume) swab out his barrel. This got to be such a task that he had to hold the rifle while his buddy tried desperately to remove the rod. Essentially a crew served weapon

. What gives there?
Well when it comes to black powder rifles you have to clean out the bore after every few shots to remove black powder residue and lead debris. That makes ramming easier and gives better accuracy. It sounds like his ram rod got stuck, probably on the rifling inside the barrel. I've had it happen to me a few times. Usually though I can get it unstuck by myself. I've never had a case where it took 3 to four guys to pull a stuck ram rod out of the barrel. At the most it might take one other person to help out if the ram rod is really stuck but that doesn't seem to happen very often. I wasn't there and I don't know what gun they were using so I can't really say what was going on and why they were having such problems. That is more of a rifle problem though and it shouldn't be to much of a problem for a pistol shooter.