I'm on Verizon because I have to be. My company's cell phones are all linked to one account. My wife has a seperate Verizon account. You NEED TO WATCH THE BILLING CAREFULLY. They will screw you intentionally.
Don't let this happen to you:
Her billing period ended on the 9th of the month. In previous months, the cutoff time was 5 PM EST. Any callls made after 5 PM were always billed on the next month's cycle. In September, she was right on her minutes. Maybe one or two under her allotment.
On her way home from work, she used her SYNC in the Ford Escape to make a phone call to her sick sister. It was 4PM PST, 7PM EST. She talked for the entire 30 minute trip. Verizon didn't cut off the billing time until 1AM. That's 28 minutes @ .45 a minute.