Door-to-door is a canvassing technique that is generally used for sales, marketing, advertising, evangelism or campaigning, in which the person or persons walk from the door of one house to the door of another, trying to sell or advertise a product or service to the general public or gather information. People who use this sales approach are often known as traveling salesmen, or by the archaic name drummer, and the technique is also sometimes called direct sales. A variant of this involves cold calling first, when another sales representative attempts to gain agreement that a salesperson should visit.

Sales are activities related to selling or the number of goods sold in a given targeted time period. The delivery of a service for a cost is also considered a sale. A period during which goods are sold for a reduced price may also be referred to as a "sale".