Internet usage'ometer

[japlatform]

Does anyone know if there is a piece of software that will tell you much much you've uploaded/downloaded? I live out in the middle of nowhere and satellite/wireless internet is the only thing I can use, which limits me to 60 GB per month (or 16 gb per month, which is $6 less). There are no 'unlimited' plans, so I need to CAP my internet use (I'd rather not have to turn my computer off or unplug my connection) BUT if that's the only option then so be it.

Thanks