Cloud Questions

I have a WD MyBook external hard drive. Also, an Iphone with Icloud, a pc, and an android. I am frequently on the road and need to access my files as I do video and music editing and do not want to carry the external hard drive around. Is there a simple, easy to use, affordable cloud service that i can back all of my data coming from multiple devices (2 pcs, iphone, android tablet, and WD MyBook External Hard Drive) onto, access the data from any device, anywhere? If so, how much room and how much?