Suggest free Bandwidth Monitor for Airtel Broadband

Hi,
I am using Airtel for my internet cnnection but some times the bandwdth of the internet is inappropriate so, there comes a break in the usage and my work too. Some time it is too low that I have to stop my work and restart it after soem time.
I do not like that hurdel in between of my work so, I am now searching out tha bandwidth monitor which is able to show me bandwidth but, it should not be very costly a cheap oen can also do the work.
The only thing is that I can be aware of the speed of my internet connection as well as how much data I have used so that I can use it more efficiently without affecting my experience because of slow speeds after AUP.

can anyone help me out to find out such a monitor if can please do reply as soon as possible.