Determine how many calls you're likely to make, when you're likely to place the calls, and what days you're likely to make the calls.
Carriers provide a variety of pricing plans.
Try to find a plan that best fits your calling patterns. There is a monthly access fee and charge for airtime. If you plan to use the phone in emergencies or only occasionally, you may want to select an economy plan. Many carriers offer plans that provide a certain amount of free minutes usage. If you plan to be a heavy user, you should consider getting a service which provides a higher monthly fee, several free hours, and the lowest rate of extra air time.