When I bought my truck I swear that the salesman had factored the cost of a spray-in liner into the price of my truck but when I checked back a few days later he said "Nope, check your bill of sale". This despite the fact that I told him I wanted a spray-in liner repeatedly during the deal. Ah well, my bad for not checking the bill of sale more thoroughly before signing.
Worked out better for me though, the dealership wanted to tack on $600 for a Line-X spray-in liner. I took it to Line-X myself and it only cost me $492 after tax.