[PC, Epic] Tom Clancy's Rainbow Six Siege Deluxe Edition $8.99 @ Epic Games

Note: Buying a ubisoft game on epic games is like buying a steam game on Fanatical/Greenmangaming/Indiegala. You do not have to have the epic games launcher open whenever you play a ubisoft game. (but you will have to do it the first time for epic games to tell ubisoft you own the game)

Also its a free weekend on Steam and Ubisoft if you want to try it out first.

Deluxe edition $9.99 on Ubisoft. Not on sale on Steam for some reason.
Base edition $5.99 on Ubisoft, Steam and Epic Games