You are technically "unlimited". However, depending on the ISP, they start throttling you (heavily, I might add) around 300-350 GB of usage.
How...? We have 250gb (or 200gb, can't remember) and I can upload a few videos to Youtube with no problem whatsoever...
That's bad. Very bad. No offense, but your family is either: Poor, strict on internet allowance for you guys, old fashioned or chose a wrong deal.