To be more clear, all of the contents of the Tyranny of Dragons modules is in the Handouts and Characters in the Journal of a Game created from the Module. That is the Product that Roll20 sells. I'm not aware of a PDF copy that is for sale, but if there is one, you'd buy that from Wizards of the Coast or one of their vendors. Specifically, you don't need a PDF to run the Modules with Roll20, everything you need for the Module (indeed, everything included in the physical book) is included in the Handouts and Characters in the Journal.
