For those looking for the lowest price point within a single year, specific sales events are the most reliable opportunities:

In general, the best time to buy a game console is during the in November and December, when retailers offer significant discounts, "free game" bundles, and hardware price cuts. If you miss the winter holidays, mid-July's Amazon Prime Day serves as the next best window for major hardware and accessory savings. The Strategy of Timing: A Guide to Purchasing Game Consoles

saw price drops of $100 or more at retailers like Amazon and Best Buy.