Salesman

A sale is the exchange of a commodity or money as the price of a good or a service.Sales (plural only) is activity related to selling or the amount of goods or services sold in a given time period.

The seller or the provider of the goods or services completes a sale in response to an acquisition, appropriation,requisition or a direct interaction with the buyer at the point of sale. There is a passing of title (property or ownership) of the item, and the settlement of a price, in which agreement is reached on a price for which transfer of ownership of the item will occur. The seller, not the purchaser generally executes the sale and it may be completed prior to the obligation of payment. In the case of indirect interaction, a person who sells goods or service on behalf of the owner is known as salesman or saleswoman.

In common law countries, sales are governed generally by the common law and commercial codes. In the United States, the laws governing sales of goods are somewhat uniform to the extent that most jurisdictions have adopted Article 2 of the Uniform Commercial Code, albeit with some non-uniform variations.

A person or organization expressing an interest in acquiring the offered item of value is referred to as a potential buyer, prospective customer or prospect. Buying and selling are understood to be two sides of the same "coin" or transaction. Both seller and buyer engage in a process of negotiation to consummate the exchange of values. The exchange, or selling, process has implied rules and identifiable stages. It is implied that the selling process will proceed fairly and ethically so that the parties end up nearly equally rewarded. The stages of selling, and buying, involve getting acquainted, assessing each party's need for the other's item of value, and determining if the values to be exchanged are equivalent or nearly so, or, in buyer's terms, "worth the price". Sometimes, sellers have to use their own experiences when selling products with appropriate discounts.

...
Wikipedia