I took a glance at some freely available online scripts of Category Theory, but I suspect I would get stuck quickly, as many examples presuppose some knowledge of Algebra which I don't have. I'm mainly interested in Category Theory because of its foundational role in logic, so I think that a book/script written from that standpoint would be beneficial for me. I would especially appreciate if the material was free, as I'm not very rich. (Though this shouldn't discourage you to also recommend non-free resources.)
Thank you very much. :)
I recently bought Goldblatt, TOPOI, The Categorical Analysis of Logic, Dover publications.
It might interest you. I got it through Amazon.