Many models also allow the ringer to be completely turned off. This is a great feature for meetings or any other time you do not want to be disturbed by the ringer, but want to leave your phone on. You can call anywhere unless you put international restrictions on your plan. You may have to be in your local calling area to initiate the call depending on the plan you have. Your first cellular bill is usually larger than your average monthly bill.
Many carriers charge an activation fee to set up each line.
Carriers have set billing cycles. Most likely, you will have a partial or pro-rated month. You may have used more minutes in this month, as well. Keep in mind, the prorated amounts are daily. That means, if you contracted for a 300-minute plan, your prorated amount is for 10 minutes per day.