That depends, is it a $60,000 unit or a $10,000 unit? Do this, find out the "real" MSRP, now take off 1/3 (33%). Even better if you can get the "real" dealers cost number to start with. Now, how much profit do you want the dealer to make? Remember the dealer has to make some money and the salesman has to make some money. Now how much overhead to you want the dealer to have. He has to pay the light bill, the utilities, the bookkeeper, etc. Now how much is reasonable for a PDI? You want them to spend 6 minutes with you, hand you the keys, shake your hand, and send you on your way? Or do you want them to spend 4 hours with you and go over everything with a fine tooth comb (you're going to get what you pay for). Any extras you want thrown in, propane tanks - filled, sewer hose, extension cord, water hose, chemicals, etc. Add them all together and you have a $$$ to shoot for.