EC2 is indeed very expensive for Windows hosting. A c1.medium instance on EC2 reserved for 3 years is $42/mo Linux and $116/mo Windows - that's nearly triple the cost for the same hardware!
Another option is to switch to mono and run your .net apps with EC2's Linux prices. Then it's even cheaper than Azure. This is what I did for my current project.
Another option is to switch to mono and run your .net apps with EC2's Linux prices. Then it's even cheaper than Azure. This is what I did for my current project.