Amazon has XBOX Live 3 Months for $15 and you get another 3 months for free. Basically getting you 6 months for $15.
I am unsure if you can buy two of them for a total of one year for $30 but it's the best deal I've seen for XBL Gold in a while.
EDIT: Appears limit 1 per Amazon account so can get 6 months for $15 unless you have multiple amazon accounts of course.
2ND EDIT: Seems this is an error. The $15 price is supposed to only be valid when you buy an XBOX One console, the B1G1F is not an error/glitch but the price of $15 by itself is. So buy it if you want ASAP.