Advertising information input control module of a POS system receives
advertising information, and a billing amount calculating module calculates a billing
amount based on advertising information received by input control module. A payment
confirming module confirms payment of the billing amount calculated by the billing
amount calculating module, and an advertising information storing control module
stores the advertising information in a storing device. A check-out information
input control module receives input of customer check-out information, and an advertising
information retrieving module retrieves the advertising information stored in the
storing device. A printing data generating module synthesizes or combines check-out
information with the advertising information so as to generate printing data, which
is output at a printing device, and printed as a receipt with an ad.