I've only ever used S3, but some of these AWS offerings do look interesting for my little projects. My question is, how do hours get calculated for billing? If I had my super low traffic blog using RDS, would I incur a few microseconds of time per DB hit, or is it rounded up to an hour, or is it the total time the DB is available period?
You would be paying for 24 hours each day. You are renting a managed virtual server, and you pay for each hour this server is running in addition to usage fees for storage and IO operations when it's actually being accessed. It'd be $20-30/month to host the database for a very small blog.
