Internet users who use the Internet for light surfing or email sending/receiving benefit from paying for the time they are online and nothing more.  Any unused time, minus the minimum 100 minutes*, is rolled over to the next month.

*There is a minimum usage requirement of at least 100 minutes per month.  If you use more than 100 minutes during the month you've met the requirement and there's no additional charges.  If you use less than 100 minutes in a month the difference of what you used and 100 minutes is taken off your account.  
i.e. You start with 1000 minutes and use only 75 minutes that month.  We'll take 25 additional minutes off your account so your balance of minutes at the end of the month will be 900 minutes.