well realistically a license isn't going to be valid without them knowing the domains they will be displayed on. Most reputable content providers i know would require that info signed and returned before you could use it.
Im sure most content providers aren't going to hassle you for putting it up while you send in the info. But i would be very suspect of a content company that let you use content without any such information being signed as the content will most likely be overused ( i.e. no license requirements means 1 person could have the same content on 5000 domains for the same price you have it on 1 domain)
www.adultczechcontent.com has good instant content in many niches for cheap prices