I like cotton cloth. No fancy crap. Just cloth. The cheaper the better. Old T shirts cut in to pieces are good but why bother cutting them up yourself. They are cheap enough cut in the box.
plain, pure cotton flannel, but then I own a full set of arch punches in the correct sizes to punch them out by the dozens with one whack of the mallet.
I do wash it first, to remove any sizing. Typical price on sale is $.99 a yard (one yard by sixty inch wide). Makes a LOT of patches.
Actually, I prefer the patches that Sinclair's sells - they seem to hold a lot of solvent very well, and I just slosh the stuff on... I follow up cleaning with an oiled Butch's twill patch, since they don't leave any threads behind...
I think I'll stick to punching them out. I've used Brownells patches, good stuff, but a tad expensive. I live right down the street from Sinclair's, great place to shop, but again the patches are a bit expensive. But then most my shooting is done with revolvers, you know how many patches you go through cleaning a revolver???