Quoted from TBatti:
Make that 4,000 plays. take off maybe $2,500 sound about right?
This is a tough discussion. What if it was 30,000 plays? Do they have to pay you to take it? Where is the cut off?
It really boils down to the condition of the game, regardless of the amount of plays. If it came down to amount of plays on route, every B/W title would be free, since they have all been routed heavily at some point (excluding the ultra rare HUO titles from the early 90's).
The first MM I purchased had over 50,000 plays on it. I certainly paid more for it than the operator did when he bought it new.