The first way to get Free Fuel at FarmVille Free Fuel Week is very simple and you are not required to do anything in fact> :)
Every day when you log in to FarmVille, you will get free tanks of FarmVille Fuel as a nice gesture from Zynga Gods. Every day, you will get more and more fuel tanks if you come back in a row. So make sure that you log in (at least once) daily to get more and more fuel.
On first day, you will get this message:-
So you can just have fun, while you get your free FarmVille fuel automatically.
Check this out to see: 2nd Method of getting Free Fuel at FarmVille
You can also get more free fuel by using: 3rd Method of getting Free FarmVille Fuel