Dealer Mark up on new mobile and manufactured homes

For negotiation purposes, I would like to know what most dealers mark up their new mobile homes from wholesale, manufactured prices. I would also like to know the mark up on manufactured homes. How is their business structured? Do they pay for their inventory on their lots or do they pay once they have closed the sale. Do they employ the movers and set up or do they contract this out What about commision on sales to the salesperson? Are most dealerships independently owned or corporate? I realize that every business is probably structured differently, but if you have any insight please drop me a line. We all know where the real money is at, but I have multiple businesses and am contemplating getting into the formal dealership business because of my unique circumstances.