I see 85 1.8's going on ebay for around $350, a couple got sniped for 250-275. Seems reasonable. Really good lens. Fixed length though...
You can get a 55-250 f4-5.6 for less than $200. Standard kit telephoto
You can get a 70-200mm f4 for as little as $500, to as much as $900. Another really good lens.
Just starting out, I might go for the 55-250 if I needed a telephoto. Used camera lenses tend to hold their value pretty well so you'll usually get a lot of your money back, unless you buy new.