If you want it on a permit (PFA) then it will be the PA18 95, or L18c it has the wonderfull Continental 90HP( like most of the other oldies), no flaps, will take 400 lbs of bodies, plus 200 Lbs of fuel/ baggage etc. Quite a bit more expensive than the others, but just as cheap to maintain and run, but must be hangared. You're probably looking at 22 to 25K to buy, and most will be hand swung, which adds to the charm IMHO.
CC