STEINS;GATE SERIES BUNDLE on Steam
store.steampowered.com

Or get the individual games à la carte

  • STEINS;GATE ($5.99 / 80% off)
  • STEINS;GATE 0 ($6.99 / 80% off)
  • STEINS;GATE ELITE - Bonus Content Bundle ($11.99 / 80% off)

Also STEINS;GATE: My Darling’s Embrace is ($5.99 / 80% off)