How long has it been sitting? If you want be fair to yourself and the buyer, get the ski running. Do a compression check. Put it in the water and ride it. For me, if a ski was running when it was parked means little. It is the now condition that matters. For me, I know it needs a top end and carb and fuel system rebuild (complete). Wear ring replaced maybe but jet pump oil change for sure.
Non-runing ski, body in good shape, electronics work with a trailer included I'm not paying over $500. Reason is, little maintenance was ever done and any repairs are likely jack leg and must be redone. Exhaust pipe leaks, etc.. I have yet to buy a ski that surprised me in a good way. LOL
Running ski, good compression looks good no reason you can't get $2500 or more for it with todays prices.
This is in my area. There are probably people that would be $3k for that ski.
Hope this helps a little.