When a Dealer charges a PDI fee, I would ask for a itemized list that details what that includes with a detailed check off that EVERYTHING on that list has been checked and verified to be correct. NO DEAL unless that list is supplied and you have the option to cancel that deal with FULL refund of any money put down if when you arrive and inspect that RV, ANY of the PDI items are not to spec. PDI charges are how most Internet dealers pad their profit. IF any Dealer "gives" you a full Tank of Gas or Diesel, well, you were SCREWED on the deal at the get go. IF you negotiate a full tank of Fuel, then that cost will be hidden in the deal and you WILL be paying for that $200 to $500 in fuel. FULL LP should always be include regardless of price. That will cost them less than $50. $600 for a Diesel PDI will be about 4 hours labor, not including the cost of Labor and Materials to fix defects found. It is very difficult to go thru a USED Diesel and check chassis and coach items in 3 to 4 hours. Now, if they are only checking appliances and other operational items, then that is within the time frame. That is CHECKING only, not fixing the items that need fixing. You could also ask and have a signed contract that states if you find ANY item on the $595 PDI checklist defective, then you get a full refund of the $595. Then they still must check and fix the items that are defective. If you are traveling a long distance and you find defective items, have in the contract they will pay for you to stay in a Hotel while they fix the items. Doug