DARUSHIMO

(b) Meaning of “Free”. (1) The public understands that, except in the case of introductory offers in connection with the sale of a product or service (See paragraph (f) of this section), an offer of “Free” merchandise or service is based upon a regular price for the merchandise or service which must be purchased by consumers in order to avail themselves of that which is represented to be “Free”. In other words, when the purchaser is told that an article is “Free” to him if another article is purchased, the word “Free” indicates that he is paying nothing for that article and no more than the regular price for the other. Thus, a purchaser has a right to believe that the merchant will not directly and immediately recover, in whole or in part, the cost of the free merchandise or service by marking up the price of the article which must be purchased, by the substitution of inferior merchandise or service, or otherwise.

(The emphasis is mine.) (See also “Advertising and Marketing on the Internet: Rules of the Road” and this article about a new law in MA: “A New Law Could Change the Way You Build Database Applications”)