The annual Xbox Spring Sale is underway, offering steep discounts on some big names for both Xbox One and Xbox 360. The sale is running until April 17, next Tuesday.
The full list is here, but only the discounted percentage is listed, not the whole dollar retail price. Some deals are for Xbox Live Gold members only, and in other cases they will save more than the general public. Some games have been past selections in the Games With Gold lineup (Sleeping Dogs and Thief, repeatedly) and some of the Electronic Arts titles are available, or will be, through the EA Access library of games.
Still, Fallout 4 is $19.80 (for Xbox Live Gold members). So is Just Cause 3 and Borderlands: The Handsome Collection (which bundles Borderlands 2 and Borderlands: The Pre-Sequel). Deus Ex: Mankind Divided is $18.00 and Quantum Break is $24.
For Xbox 360, Call of Duty: Black Ops 2 is $20, and note that game was just recently made compatible with Xbox One. Likewise, Red Dead Redemption, at $15, is playable on both consoles. About 40 Xbox 360 titles on sale are backward compatible with Xbox One.
Again, the list doesn't list whole dollar sale prices, because Xbox wants you to click through to its marketplace, but with about 400 titles listed (some are special editions, DLC extensions, or season passes) there's a good bet something you've been meaning to get around to is going for more than half off.