A new head's going to run you $40-45. Cash in your saved pennies or whatever.

If you want to find a cheaper head, you've got two options I can think of off the top of my head: discontinued heads or Mylar. Steve Weiss has
Pearl Finalist "Tendura style" heads for $19.95. I've never heard or played 'em so can't say anything about their sound or feel. Woodwind & Brasswind has
Remo FaLam natural (yellow) heads for $22.76. Decent Mylar heads like the
Remo Powerstroke 77 are also in the $20 range, but they're more expensive than Kevlar in the long run because you'll have to replace heads more frequently. (If you're looking at a Black Max, Mylar probably isn't the sound you want, anyway.)
IMO, you really don't want to spend good money on a used head. When tensioned, a head conforms to the drum and the tension applied to it. If tuning tension wasn't evenly applied or the original drum wasn't perfectly round, you may have a hard time balancing the head after you re-mount it. Also, most used heads were taken off the drum for a reason. They're probably pretty close (or even past) the end of their useful life.