BitMeter OS is a free, open-source, bandwidth monitor that works on Windows, Linux and Mac OSX
Source Bitmeter Homepage: https://codebox.org.uk/pages/bitmeteros
BitMeter OS keeps track of how much you use your internet/network connection, and allows you to view this information either via a web browser, or by using the command line tools.
To install Bitmeter just visit the download page and choose the .Deb that meets your systems requirements:
That's it enjoy.