First, what's the engine power?

If less than 20 horsepowers (not a soviet "at the engine", but at the propeller; my 5 h.p. Tohatsu goes faster than 8p.s. Veterok), its completely meaningless. For the beginner you'll need at least 50.

Than, the waterski I saw at Sportmaster two month ago was like $500-$550 for both waterski & hallyard. It was new, used should be cheaper for sure.