Download limitation win7

Can somebody help me by teling me is there a way to limit internet download on network with 20PC? because, there is sombody who is downloading all 12MBits/s and the rest of as are in problems..
i need it to be freeweare because it’s a buissnes network.
Answer #1
Untangle, pfSense, ClearOS. Anything would work.
Answer #2
It all depends on how the PCs are connected to the internet,If there’s one central server that has direct internet connectivity and spreads
it out to the others via switches,The above suggestion would work fine,If however it’s based on a router+switches then that leaves you
with 2 options:
1. Use the QOS function in the router,If it has one,Or purchase one that does.
2. Install a bandwidth limiting app on each PC and configure it accordingly (I.E Netlimiter,But this is not freeware as asked)
Edit:Also,If the router is supported by DD-WRT (3rd party firmware),No need to buy a new one,Just flash it and you’ll have QOS.