Pay once, get a server for life. Servers start at $35 for a 1 CPU / 512MB RAM / 10GB SSD. Watch their Twitter account because they have coupons for 50-60% all the time. On Black Friday they had coupons for 90% off.
Specs
Pros
Pro Cheap. Like, really cheap...
With the coupons they offer all the time you really can't beat the price when you consider its a one time fee.
Pro Good variety of OS selections
You can load several variants of Linux (Ubuntu, Cent OS, Debian, etc.) and they even let you throw Windows 7 on them (security nightmare, but whatever). You have to enter your own Win 7 key.
Cons
Con Service
You get what you pay for. Don't expect stellar customer support or blazing fast boxes. I only use these for really basic things. I have one running GitLab to back up my code, a couple running Cloud 9 so I can dev straight on the server, and one as a proxy for when I'm on public wifi or something. Don't think you are going to run your company's web site on these servers.