Online booksellers-The List?

[I did an archives search, and this forum seems to be the best place to make this post]

I am hoping the members here can assist.

I am seeking to create a list of online booksellers that they recommend, over and above the obvious ie. Amazon.

I know of bookdepository which purports free shipping (but have not had the occasion to use as yet).

What about others you know of and can recommend? Why?

Thanks.

bookdepository is differentiated by the fact that it has free shipping (it claims). I do not yet know first hand if this is true or not.

As for those you've mentioned, are they simply smaller Amazon clones, or do they have something (else) that makes them stand out?

Thanks.