It also depends on the size of the contract, and whether it is stripped of it's points or if there are points that can be banked from last year.
We just reached an agreement with a seller. It was a little higher than I wanted, but it had banked points that I can use so it worked out. The smaller the contract the more they are going to want, as it seems they are easier to sell. I know I don't have the money to buy a larger contract without financing. The smaller one I have, I do have the money on hand. I think 9 to 12,000 is more manageble for people than $15,000 to $20,000. So if you are in the market for a 200 plus point contract, you can probably negotiate a price at 90 per point or less. Getting a 100 point at that price may prove to be more difficult.
It also depends on the how motivated the seller is to sell. Ours was willing to wait a while for his price. I ended up being ok with his price, and it was the exact contract we wanted, use year and all. We really wanted June, and that's what we got. April and March would have worked for us as well, but I wouldn't have taken this price if it wasn't June. I would've waited.
I would offer $80 or in the low $80's and see what they counter with. It's a business transaction so keep the emotion out of it as much as you can. Don't worry about offending anyone. They are going to want more, and you are going to want to pay less. But if you can come to an agreement that both can live with, then you will have your contract. Also MF and closing costs can be negotiated as well.