Autosport.com is having a promotion on its Plus membership yearly subscription at US$14.99 (70% off their normal price) as part of the 70th Formula 1 Anniversary celebration.
For me this is one of the best sites if you follows Formula 1, Motor GP or WRC. Plus membership gives you unlimited access to their journals and premium contents (in-depth analysis, extensive report, prediction ect…) which I personally found them a level above other sources (e.g. Skysport, BBC, Planet F1, Racefans…)
They also have the digital version of the paper-base Autosport magazine which you have to pay extra to access, but for some reason right now I can download them at no cost so pretty happy about it too.