There appears to be two programs with that name, one with a space (Net Meter) and a free one without space (NetMeter). Which one do you have?
I use Free ThinkBroadband's meter. Once set up with details it tells me how much of my monthly allowance I've used when I hover cursor over icon. Various alarms can be set to alert me and it gives a full log of daily, monthly usage etc. (though I have disabled the Automatic file sending testing feature)