Web hosting provider recommendation?

[Morganite]

I'm far from being an expert, but you might check out railsplayground.net . I had an account with them for a while (before the purpose for which I got it stopped existing), and I think they meet most all your requirements. (On the price issue, a level 1 developer account (3gb storage, 30gb/month transfer) is $5 a month, although that level requires paying a year at a time.)

-Morgan.