It shall be unlawful for any person who is engaged in the business of financing the purchase or sale of motor vehicles, or of buying conditional sales contracts, chattel mortgages or leases on motor vehicles sold at retail within this state, to accept or receive, or contract or agree to accept or receive, either directly or indirectly, any payment, thing, or service of value from any person who is engaged, either directly or indirectly, in the manufacture or wholesale distribution only of motor vehicles, whether patented or unpatented, if the effect of the acceptance or receipt of a payment, thing, or service of value may be to lessen or eliminate competition, or to create or tend to create a monopoly in the person who accepts or receives the payment, thing, or service of value, or contracts or agrees to accept or receive that thing or service of value.