cheaper and simpler than separate accounts--just be sure to keep an eye on chatty teenagers. What's more, family plans include free in-network calling, which means that calls to your family members--or any other carrier subscribers--aren't deducted from your allotment of anytime minutes.

With Sprint's family plan, for example, you can get two phone lines on five different pricing scales. The cheapest plan gives you 550 anytime minutes for $59.99 per month. Alternatively, the most expensive plan entitles you to 3,000 anytime minutes for $149 per month. As you can expect, however, a couple of restrictions can apply, depending on your carrier. Additional lines over the first two are an extra $10 a month (at least with Sprint), all participants may have to carry the same model of phone, and all family members usually have to reside at the same address.