Rumors have surfaced online that Destiny will be going free-to-play. This comes after a listing on the Microsoft Store marked the base game as free. The Destiny Reddit also noticed that base versions have been pulled from both the Sony and Microsoft Store and the only version available for purchase is $10 Destiny: The Taken King bundle.
If this happens, it will mostly likely mean the base game will be free-to-play and both expansions will cost money. Keep in mind that Bungie nor Activision have confirmed anything.