DropBox

Maintaining a professional operation without breaking the bank is crucial to freelancing.   I have found these tools to be invaluable to my business and hope that you try them for yourself.  Note that some of the links below have affiliate codes in them, but I am not otherwise being asked or compensated to write reviews for these services.
 

Full disclosure : If you use any of the DropBox links in this article to visit their site, and then sign up I will get some extra storage space for the referral.  And no, I am not writing this post just to get extra space, I really do like DropBox.