If you exceed the included data transfer amount within in the calendar month, then you may be charged an additional data transfer fee. 100 GB of data transfer usage is included with all levels of internet service at no additional charge. High Speed 55 and above also include an additional 200 GB of usage, for a total of 300 GB.
The fee is $5 for the first 1-25 GB over the usage amount included with your service level, and $5 more for each additional 1-25 GB over that. For example, if the data transfer amount included with your account is 100 GB, and your use during the calendar month is 142 GB, then your Data Transfer Fee for that month will be $10.