I bought the 13 piece punch set from Princess Auto. I use different card stock, cartons, boxes, dollar store felt and cork. When punching out card stock, I always measure the final thickness with micrometer (as it compresses in punch), and sort in dollar store portioned box.
Make sure to get a solid base to punch out circles, I got an old stump that I keep in reloading room and grind down when needed I get too many rings in it.
If you want to go the cheap route, many shops on here have factory wads for sale.
As a note, I make my own Black Powder and lead shot. When is comes to wads, I either use cotton batten or my overshot card stock depending on the load and gauge (12/20). I have 2 H&R single shot shotguns that load for BP (SHTF). To treat like a Musket, I cut the plastic off high brass shotgun gun shells and carry 209 primers, replace the primer (I have a tool and base plate, I made), press in new primer. Load in barrel and close - Pour ### gr of homemade powder, wadding, swan shot (or Princess Auto Steel sand blasting 6.5-7.5 size, or Crossman BB's, PA steel BB's), and a heavy cork or felt wad.
This set is up repeatable, with minimal effort and will last a long time.
I cant take credit for the idea - a guy on youtube set me down this path. Work up your loads carefully, as you really have no idea of the pressures involved.