Amazon offers Prime members Destiny: Standard Edition for PlayStation 4, Xbox One, PlayStation 3, or Xbox 360 for $19.99 with free shipping. (Non-members can spend $35 to qualify for free shipping; otherwise, it adds $4.98. Toys "R" Us charges the same via in-store pickup, although stock varies by ZIP code.) That's $5 under our mention from two weeks ago and tied with the lowest price we've seen for this game on any platform. (It's also a current low by $5.)
Update: Note that some versions may be temporarily out of stock, but can still be ordered at this price for delivery when available.