Like for Step 1, Step 2 CK has a handbook, which you should be aware about, and it contains a 3 block - 131 question exam at the end with answers. Some people call this the "Free 150", i think, unless there is another exam I am unaware about. But this exam is OFFICIALLY released by the USMLE on their website and you shouldn't neglect it.
Here you go!
And great luck!
If this link doesn't work, try going and clicking the "handbook"
in the right margin HERE.
Same thing. Cheers!
Also! USMLE Rx offers a 20 question Free trial of their question bank (and so do others... but its a nice little review quiz for Step 2CK material... here is the link: