Recently it was "free" on GOG for Amazon Prime subscribers:
Comment has been collapsed.
3 Comments - Last post 15 minutes ago by Choco316
8,675 Comments - Last post 1 hour ago by WaxWorm
33 Comments - Last post 2 hours ago by jiggakills
650 Comments - Last post 2 hours ago by RiderOfPhoenix
27 Comments - Last post 3 hours ago by UraniumFalconPunch
25 Comments - Last post 3 hours ago by CedarTeeth
278 Comments - Last post 5 hours ago by steveywonder75
13 Comments - Last post 3 minutes ago by ColdOut
53 Comments - Last post 24 minutes ago by Devirk
197 Comments - Last post 27 minutes ago by Kegfarms
103 Comments - Last post 31 minutes ago by Habaruku
34 Comments - Last post 33 minutes ago by hsunkuei
206 Comments - Last post 49 minutes ago by nat24an
55 Comments - Last post 1 hour ago by Pe4enie
NOTE: There's 2 "complete the set" bundles, for owners of Slay the Spire or Inkbound, which make this even cheaper. I already had StS and I got the Slay the Spire x Monster Train bundle, which was about 10% lower than Monster Train would've been.
https://store.steampowered.com/app/1102190/Monster_Train/
Slay the Spire x Monster Train bundle
Shiny Shoe Originals Bundle (Inkbound + Monster Train)
Comment has been collapsed.