Newegg offers Assassin's Creed Syndicate for PlayStation 4 for $29.99. Coupon code "EMCRCRE33" cuts it to $9.99. With $2.99 for shipping, that's the lowest total price we could find by $9, although it was $3 less a month ago.
It's also available for Xbox One for the same price via the same code. It's a price low by $2.