I've written on this subject previously. The problem with web services is that most are designed by geeks for geeks. Very few are designed by business people for business use. Amazon changed that when they introduced web services that businesses can access and pay-for as they use. Not only have they introduced pay-as-you-go web services. They've made it real easy to get started and real easy to access your usage and bill:
To use services like S3 you don't need to call us, you don't need to set up a meeting, you don't need to enter into any negotiating sessions with us, you don't need to start writing custom contracts, and you don't need to send us any money up-front. We designed this service and all of the infrastructure around it to be self-serve, straightforward, and trouble-free.
If it were only that easy to get a cell phone.
Bonus Link: They've also made it real easy to store and access media files through an API.