Amazon is selling 1-Year of PlayStation Plus Membership for $49.99. It’s a digital code, and will be available in your Amazon digital library after purchase.
Also, 3 months of PlayStation Plus membership is for $17.99.
Please note that this is only for US region, but if you’re outside US and use a US PlayStation account, then also you can buy it. Only thing you need to is add a US address to your Amazon account.
PlayStation Plus membership gives you free games each month for PS4, PS3 and PS Vita.
12 months Playstation Plus USA on Amazon for $49.99
12 months Playstation Plus USA on CD Keys for $47.99