A request for content is received. First content is selected for the request. The first content is selected from among multiple content items based on information in the request, a characteristic of how the first content is to be presented, and a stored pricing threshold value selected based on the characteristic. The characteristic of how the first content is to be presented includes an amount of available space that is occupied by the first content when the first content is presented. The selected first content is provided for presentation by a publisher that provides second content.