A survey carried out by price comparison website Moneysupermarket found out that nearly a quarter of mobile broadband users are unaware whether their service comes with a download limit.
Half of those questioned said that they were not even aware what their download limits were. Opium Research interviewed around 2000 adult mobile broadband users.
Furthermore, the report found out that three in four mobile broadband users face heavy surcharges for exceeding their downloading limits, often without knowingly going over their download quota.
The price mobile network operators charge for the excess usage varies enormously with T-Mobile being the most lenient of the five major networks surveyed.
While T-mobile merely gives a slap on the hand for heavy usage (which translate in a limitation or throttling of your download speed), others go much further.
Vodafone will charge £15 per extra gigabyte used, Virgin Media and Orange £14.95 while O2 users will fork out a staggering £200 for each gigabyte used and Three users half of that amount.
James Parker, manager of mobiles and broadband at Moneysupermarket, told BBC that "Dongle users are most at risk of incurring charges from exceeding download allowances as limits on dongles tend to be much lower than fixed-line packages".
3 Network's cheapest broadband offer is the most restrictive as well - £10 for 1GB and users only have to add £5 to get an extra 14GB worth of data.
It is useful to remember that the data transfer quota is valid for download and upload as well. Also noteworthy is the fact that a quarter of people acknowledged that imposing download limits forbids heavy downloaders from abusing limited resources.