I have free version for DropBox. It is more than sufficient in this age. I remember when the space on disk and in cloud was a challenge and it was not so easy to have a common ground of transferring the files or any other thing. Collaborating is also doable.
Considering that Google gives 15 GB without even charging a penny, why would one want to pay for this DropBox account? A free version of Dropbox is sufficient - to transfer the files from one computer to another one.