One general trend in cloud hosting is to have multiple sources of the cost for a system. For instance with EC2 you have a per hour price for the virtual server

One general trend in cloud hosting is to have multiple sources of the cost for a system. For instance with EC2 you have a per hour price for the virtual server and a per gigabyte price for data transfer. If you want any kind of permanent storage that's a separate thing with it's own per gigabyte stored and per gigabyte transferred costs. Not only is it easy to miss these, but they're not things you pay as much attention to in a typical hosted server environment.