Here's a start for your research.
https://www.google.com/search?q=monitor+internet+use+with+squid
Hello guys. I have a project in mind where I want to create a system that will connect to my router and it will monitor the amount of bandwidth being used by users connected to it, kick out users and even ban some. I want to create a system that will enable me to resell my Wi-Fi connection...thus monitoring how people will pay and the bandwidth allocated to them. I have quite some knowledge in computing but I don't understand much of the networking stuff. Any suggestions are very welcome.....all I want is a hint of what to do and I won't mind doing more research. Thank you

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic