According to WotC / Hasbro Senior Manager for Research, D&D Mike Mearls, Basic Dungeons & Dragons will be free in PDF format. This makes a whole lot of sense. A great number of games including Paizo Publishing’s Pathfinder RPG have versions you can download in PDF format or access for free online, as well as the many great retro-clones of D&D.
D&D 5 (WotC wants to strip away the “5” for marketing purposes, but we need to know what version we are talking about), is due later 2014 with the release of the D&D Starter Set, Player’s Handbook, Monster Manual and Dungeon Master’s Guide.