An advertisement provider issues coupons to an audiences of television set in exchange of viewing a commercial message and receives advertising rate from the advertiser of the commercial message in exchange of informing of the coupon issuance. A television station allows the audience to decompress a downloaded digital image data of a television program in exchange of presentation of the coupon. The television station receives allotment of the advertising rate in exchange of informing of the coupon presentation form audiences. The television station sorts the presented coupons by the advertisement providers to inform each advertisement provider of the coupon presentation. The television station allows the decompression even in a shortage of the presented coupon, provided that it will be compensated by money or later presentation of coupon by due data. The commercial messages are provided automatically or by request. The audience may voluntarily replace television program by commercial message.