Near all time lows for these classic FPS shooters as well as the new all time low for Doom 64!
Xbox links courtesy of DealBot in the comments
ALSO on sale:
Doom 3 - $7.47 (was $14.95):
Doom 2016 - $39.95 (was $79.95):
[XB1] DOOM Slayer's Collection (courtesy of gibspmuh) - $17.97 (includes Doom1, 2, 3 and 2016):