Buy Quake!

Buy Quake from Steam:

http://store.steampowered.com/app/2310/ – Quake 1
http://store.steampowered.com/app/9040/ – Quake 1 Mission Pack 1: Scourge of Armagon
http://store.steampowered.com/app/9030/ – Quake 1 Mission Pack 2: Dissolution of Eternity

http://store.steampowered.com/app/2320/ – Quake II
http://store.steampowered.com/app/2330/ – Quake II Mission Pack: The Reckoning
http://store.steampowered.com/app/2340/ – Quake II Mission Pack: Ground Zero

http://store.steampowered.com/app/2200/ – Quake III Arena
http://store.steampowered.com/app/2350/ – Quake III: Team Arena

Buy other id Software games from Steam:

http://store.steampowered.com/app/9050/ – DOOM 3
http://store.steampowered.com/app/9070/ – DOOM 3: Resurrection of Evil

http://store.steampowered.com/sub/440/ – id Super Pack – the id Super Pack includes over 20 games from from id Software, including titles from the series of DOOM, HeXen, QUAKE, Wolfenstein and more!

http://store.steampowered.com/app/9200/ – RAGE

Get shareware Quake:

Quake 1 (version 1.06)
try the demo, buy the game, get patches

Quake 2 (version 3.21)
try the demo, buy the game, get patches
source port that enables wide-screen