It will be time soon to pick up a bargain on the Xbox Digital Store with the Xbox Summer Sale starting on July 5th. Some new games will be there too so it will be worth checking out.
[UPDATE] Worth noting that PC games from the Windows 10 Store are also meant to be part of the sale, so keep an eye out for deals on games like Rise of the Tomb Raider, Gears of War Ultimate Edition and Quantum Break.
[UPDATE 2] Items to go on sale are now listed on Major Nelson. No news yet on PC games so that info may be in error.