If doing three point hitch work is important, make sure you get one with all the 3PH hardware included. Would be hard to find used and expensive to get new if it could be ordered even. Good luck.
All you would need is the toplink, side links and the two bars. All the other hardware is on the tractor, including the hydraulic cylinder to lift the 3PH. I would imagine them hard to find used but no more than a couple hundred new if I were to guess.
If you plan to get a Top and Tilt in the future though I would say now would be the best time to get it and save yourself some money on one toplink and one side link.