How to Play D&D for Free

You don't need D&D to play D&D. There are free alternatives. Not to mention that its not hard to make your own game if you understand how table top roleplaying games (TTRPGs) are played. 

• Basic Fantasy RPG is a free retroclone of an old school edition of D&D. It's like the Basic / Expert edition (B/X) with a few modern rules. This is the GOAT! They have a downloads page where you can get supplemental books including adventures.
• White Box : Fantastic Medieval Adventure Game has a free pdf. It's a 100 page retroclone of original D&D and I love it!
• Blueholme Prentice Rules is a retroclone of an older ed of D&D taking you on levels 1 to 3.
• OSRIC 1e, which stands for old-school reference and index complication, is a retroclone of Advanced D&D (AD&D) 1e.
• For Gold & Glory is a retroclone of AD&D 2e.
• Both D&D 3.5e and Pathfinder 1e have a System Reference Document (SRD) here. I've heard PF 1e described as D&D 3.75e. An SRD is also available for D&D 5e there.
• Draw Steel by MCDM is a relatively new game with its complete rules free online (got to respect that). I've heard it's similar to D&D 4e.
• Index Card RPG 2e has a very generous amount of content in their quickstart rules. It's a very simplified version of the essence of D&D. Setting and genre neutral. Flexible. Fast. Simple.
• Olde Swords Reign is a mix of D&D 5th edition, D&D 0th edition, and then some quality new ideas. I would call this a great way to ease modern gamers into older style D&D games.
• Shadowdark has a quickstart rules set. It's a popular alternative to D&D 5e. Its similar to 5e mechanically but it has an old school feel. I hear it's a good entry point for modern gamers into older style play.
• Cairn aka Cairn RPG is a very rules lite game. 1e and 2e online.
• Black Hack RPG is a hack of classic D&D. Probably B/X.
• Lamentations of the Flame Princess is old school D&D with a weird / horror twist. The core rules are slick and free.
• Open Legend RPG is like if all the familiar assets of character creation for D&D 5th edition were broken into little bity pieces and it allowed you to make a highly customized character. It's setting and genre neutral and highly customizable. Core rules are completely online. I really like it but the barriers to entry are that no one's playing it, there are few to no other resources for it even though its open-source, and it's character creation is really involved.
• OpenD6 is an a free game different from D&D and the d20 system. OpenD6 uses only six-sided dice. It's got a dice pool system. Your stats are represented by a number of dice. For example, rather than having 10 strength, you might have 2D for two dice in strength. That's the number of six-sided dice you roll to make a strength test. The rules are modular so if you want to change it to suit your game, you can by adding or removing stats, skills, etc.
• Patherfinder 2e is here. I hear this is very different from PF 1e/
• Mork Borg has a bare bones edition for download. This is a dark fantasy/ horror fantasy game.
• Open 2d6 is a game with mechanics inspired by Barbarians of Lemuria. Roll 2d6, add bonuses, try to roll 9 or higher. Double 1s are a crit fail, double 6s are crit success.
• Open Lite RPG is a game I wrote for fun on this blog. I imagined it as a simple, rules lite game. It uses only the d20 and d6's. 

Free Settings

A setting that is ready-to-play. A setting is a defined major location for your game with one or more minor locations. It could be a town, a dungeon, and a wilderness in-between. Or a whole region of a world. Or a galaxy.

• Mystara is a classic D&D setting.
• Blackmarsh (not Elder Scrolls).
• Draconia '95 is an in-progress setting I'm working on, also on this blog. It takes place in a generic city in 1995. It's a bases for urban fantasy, sci-fi, and horror in a grounded modern setting where the best of technology exists but is not ubiquitous.

Free Starter Adventurers

What's and adventure? It's a scenario to play through with a problem or goal, a map or series of maps, monsters, treasure, etc. Sometimes adventures they have built-in settings.

• Basic Fantasy RPG's dowloads page is your friend! One thing worth noting is that all versions of D&D pre 3e are mostly compatible and easily converted, which means adventures for one work for the others. I am recommending these as good starting adventures:
• BF1 Morgansfort: The Western Lands Campaign. This contains a starter setting.
• JN1 The Chaotic Caves
• AA2 Adventure Anthology Two, the mini-adventure Kidnapped on page 41
• Tomb of the Serpent King is a teaching dungeon. Very good!