NewEgg is offering Destiny — the 2014 base game, not The Taken King — for what is effectively nothing this weekend, though buyers will have to mail in a rebate and wait for that to be paid. The offer is only for the PlayStation 4 edition.
The offer is on this page. At checkout, buyers apply the promo code, which knocks $10 off the listed $25 price. A mail-in rebate takes care of the rest. Shipping is not free, however, with options starting at $2.99 for delivery in 4 to 7 business days. To take advantage of the promo code, one has to sign up for NewEgg's deals newsletter, too.
Be sure to look at the rebate form here to make sure you want to jump through all of these hoops. It involves cutting out and mailing in the UPC code from the insert on the game's case. There also is a whopping 8 to 10 week wait period mentioned in the terms and conditions.
But, hey, free PS4 game when it is all over. Or, look on it as a game for $15, and you find money in your pocket a couple months later.