Your $5 tier offers awesome value for money, but I think a lot of people could use one more service level below that.
Just like some years back, 256MB would still be enough for running a backup-server, a web-app with a handful of users, a mail server, and lots of other random little uses.
For something like $2.5, having even several servers like that lying around would be a complete no-brainer. You could halve the $5 level's capacity, and that would still be plenty.
I'm not sure if this would be financially viable, or worth the trouble for you, so I understand if it can't happen. Just wanted to share the idea anyway.