From the Forum Guidelines:
5. Advertisements. If you would like to advertise a product that your commercial company manufactures, or if you are an individual private seller, you can buy a classified ad in the magazine or an ad on the Web site. This includes all buying, selling, and trading. Any posts that appear to be an advertisement or transaction will be deleted.
Because FSM is protcecting is advertisors. If you offer an item for $10, and paying advertisors are offering the same item for $20, you are taking business away from them and in turn they would no longer buy advertising space. Therefore Kalbach would lose revenue and the mag would fold.