user wroteIt might be hard to find a router that limits by used volume, but I bought a router recently (tp link archer d2 from pcandparts) to have some more control over internet distribution in my house(also for the 1gbps ethernet ports which I love and the high bandwidth wifi), it does allow me to restrict the minimum and maximum bandwidth usage per device in my house and per port. I am finding it useful particularly when we have guests over, and they take the opportunity of using our internet to start watching videos.(you can create a whole other wifi called guest network and limit bandwidth on it for all guests, and have another family wifi, and then you can limit people by their ip address and bind their mac addresses to ip addresses so they never change)
If I had bandwidth problems, I would for example limit my family members to a stop max speed of 1mbps instead of 2mbps and see if that forces their usage down... perhaps it is better than outright cutting them out, because then if they ask why don't we have internet it;s awkward to say well because you passed your limit.
The router also has a priority system, where if one user has a higher priority over another user, they would be allocated the bandwidth preference. But all users get the set minimum amount of bandwidth guarrentied (as you program it in the router) the maximum that is shared gets prioritized based on the priority...
It also has statistics that allow you to see how much total bytes each ip used, though it is not very detailed and very bare bones. Useful to determine who is siphoning the connection at the given moment...
My usage for this router on the unlimited connection I have now is as follows:
I have a mini desktop downloading 24/7 every second of everyday, the router gives it the least priority with 10 kbps guarrentied speed no more and a max speed of 2mbps. This machine downloads at 2mbps most of the time, but if anyone in the house opens anything and wants to use the internet, the router automatically drops this download machine to 10kbps and gives this person the rest of the router's bandwidth, allowing me to download 24/7 and still not bother anyone at home. And it works very very well.
I did a similar thing installing DD-WRT on a TP-Link router. I had a problem particularly with iCloud and some other Google services uploading data on our 700Kbps upload pipe, which would sometimes make it impossible to game online for hours on end.
I set the maximum upload and download bandwidth, allocated a high priority to the PS4's MAC address and it's been working like magic.
I also previously had Open-WRT in which I was able to measure the total volume used and SWAT the family member who was consuming lots of bandwidth for a day by pointing them out. Most of the time, it would be something uploading data that they are not aware of. Once we turned all these upload things off, we were able to reach the end of the month with enough quota.