is there a difference between versions of IT
 

I bought a copy of IT at a used book store and its not the same version as the one in the store. Is there a difference between versions or are they all the same.

I know that most of King's books have gone through several reprints. Most likely, the one you got from the bookstore is an earlier edition than the new copy.

Basically they're the same.

I have the one with the clown on the front with the starry eyes, and my mom has the hard back version of the sewer grate with a scaly claw holding a bar on it, and we've read both, they're the same.

No it all a reprint of an earlier edition.