A system and method for sensing a seat occupancy by an individual and executing an ecommerce transaction via the individual's mobile device for the cost of a ticket based on the occupied seat. For example, an attendee enters a multiplex and chooses a theater and a seat from which to watch a movie, or a passenger enters a station and chooses a train and a seat in which to travel. In both cases, the occupancy of the seat is detected, an amount owed is determined based on the occupancy of the seat, and an ecommerce transaction is initiated via the mobile device to pay the amount. The determination of the amount may be delayed for a period after the individual has stopped moving to ensure they have made their final choice. The individual may be required to verify a relevant characteristic, such as age or membership in a discounted group.