Sale, selling, and equivalent expressions mean the attempted act or acts either as principal, agent, or salesperson or in any capacity whatsoever of selling, bartering, exchanging, or otherwise disposing of or negotiating or offering or attempting to negotiate the sale, purchase, or exchange of or interest in any motor vehicle, trailer, or motorcycle, including the leasing of any motor vehicle, trailer, or motorcycle for a period of thirty or more days with a right or option to purchase under the terms of the lease.