Let's say the actual market value of the truck is $32,000.00.
Dealer has to assume that no one is not going to exercise the option to purchase something worth $32,000 for $27,000.
If Dealer sells it to Buyer and Buyer flips it, Dealer makes nothing except normal profit.
If Dealer pays Buyer $2,000 for his option, and sells the truck for $32,000, dealer has made $3,000.00 plus normal profit.
In essence the Dealer is paying the buyer for the privilege of being the one to flip the truck...
Which leads to the question, why would the Buyer take $2,000 when he could flip the truck and make $5,000? It could be that the buyer does not want the hassle of flipping the truck, and $2,000 looks pretty good for signing a couple pieces of paper.