The Amazon EC2 Cloud is inexpensive, scalable, and you only pay for what you use. You can turn instances on or off at will which gives you extraordinary flexibility.

Each instance is the “equivalent of a system with a 1.7Ghz x86 processor, 1.75GB of RAM, 160GB of local disk, and 250Mb/s of network bandwidth.” To buy such a machine might cost $500 before hosting.