I have bought and sold 18 games in the past 2 years. As a seller, when a pin is competitively priced you get multiple offers quickly. If you have multiple offers are you going to answer a bunch of questions or respond to the guy offering full price, says he has cash, and can pick it up today? When I sold my Fish Tales I literally had over 40 offers. In most cases when I sell a game now I get 2 or 3 offers almost immediately and accept the one I like best unless I am looking for a specific trade. This week a Medieval Madness came up at a very reasonable price near me. I made a trade + cash offer and was rejected. I then sold what I was offering in trade overnight and had it picked up the next morning to offer a full priced offer for the original game, which I picked up that afternoon. Cash in hand is king when it comes to getting a game you want. If you have a $3500 budget, withdraw the cash and keep it in an envelope ready to go.
Since you (and presumably others) want to know what offers to buy games look like on Pinside, here are the last few I sold looking for cash (with names removed to protect the innocent).
Finally, here the language used to pick up a machine after my initial trade offer was rejected.