So you need a new server to test your project, and for testing its scalability you wish to have 100 servers running under your control for 10 hours. You wish to pay money for these servers as long as you actually use them, not for their ideal time. After 10 hours, you would like to throw them out. Sounds Interesting? But with usual dedicated/co-location hosting providers, its not possible. They require you to place an order, pay monthly/weekly commitment, wait for 1-4 days irrespective of the fact that you need machines only for 10 hours.