Was doing this in a discord, but it might be of more general interest and if I put it here, I can link to it. People are (rightly) flipping out about stuff going on with D&D, and looking for alternatives and yes, pathfinder, PBTA & Forged in the Dark stuff are great, but what if you got zero dollars? Here's some stuff available for free (as in beer). In no particular order:
Quest RPG
WARP (Wanton RolePlaying System)
Eclipse Phase
Stars & Worlds without Number
Lady Blackbird
edit: ooh apparently Lady Blackbird got some sequels since I last looked at it
some related hacks/expansions
Tales From the Wild Blue Yonder: The Lady Blackbird Companion
Always Never Now (cyberpunk adaptation, pwyw including zero)
Risus
Fate & Fate Accelerated
Fudge
Ars Magica 4e
Some SRDs:
Pelgrane Press Gumshoe SRD
Monte Cook Games Cypher System SRD
Chaosium (Call of Cthullhu etc.) Basic Roleplaying SRD