As used in this chapter:
I. "Customer" means any person who is seeking to purchase, is purchasing, or has purchased a used motor vehicle at retail.
II. "Dealer" means any person who is engaged in the business of selling at retail used motor vehicles.
III. "Person" means any person defined by RSA 358-A:1, I.
IV. "Used motor vehicle" means any motor vehicle as defined by RSA 259:60, I, which has been previously leased, rented or sold at retail.