Oh, there's plenty. I use DigitalOcean for my cheapo VPS. $5 a month for a not-great-but-not-horrible machine. Never tried it with MG, though, and the memory and CPU of the lowest tier are probably too low for MG. The $10/mo tier might be enough, but it's hard to say if the processing power is sufficient. The MG documentation strongly recommends multi-core and I can't say just how important that is (CPUs are really hard to put to a number, and VPSes especially so -- I mean, "1 core" doesn't exactly mean much).
You can get cheaper, though. I mostly went with DigitalOcean due to free credit from the GitHub student package, and I really liked their documentation for setting up a variety of common software (eg, to setup Postgres).
I've heard a lot about Amazon EC2, but never used it and can't say for sure if MG would work there. Don't see why it wouldn't. I have more experience with Microsoft Azure (can't say if I'd recommend that; had plenty of frustration in working with the poorly documented management API -- but you wouldn't need to use that, nor would most people, I would think). Anyway, I can't tell exactly what the EC2 instance is compared to Azure. MG provided wouldn't run in an Azure App (they're too limited with the control provided), and thus would need an Azure VM (which is a VPS).
