Manage the amount of data traffic on the Internet

[tiagopesantos]

Hello guys, does the sense pf has a tool that manage amount of access? is not bandwidth, I have squid!
ex: I have a particular client in accessing my network and when it reaches 500M access, access is blocked, back to release the next day again, or another time, like the 3G operators.
thanks for listening
  :D

please help-me