I’ve got the same setup at pfortuny.net/reflexiones plus amazon workmail and it costs me around 6$/month. Very low traffic, though. Anyway, the cost is 5$ for the mail, so the blog is negligible.

Amazon’s pricing is easy for this simple setup.

I run the same setup. Probably don't get any traffic because I don't write blog posts anymore. My monthly costs are around $ 0.70.