Tarsnap is a secure online backup service for BSD, Linux, OS X, Solaris, Cygwin, and can probably be compiled on many other UNIX-like operating systems. The Tarsnap client code provides a flexible and powerful command-line interface which can be used directly or via shell scripts.
Tarsnap works on a prepaid model based on actual usage.
300 picodollars / byte-month ($0.30 / GB-month)
300 picodollars / byte ($0.30 / GB)