While many children who are given cell phones are covered under family phone plans, prepaid phones are another option. You can purchase prepaid phones in retail stores like Walmart or Rite-Aid -- prices range from about $10 to $60 or more, depending on how fancy the phone is. Instead of signing a long-term contract to obtain service, you generally purchase a card with a set number of minutes on it, then activate the phone and minutes. Or you purchase minutes through a prepaid carrier's minute plan. In either case, when the minutes run out, your child can't talk or text anymore until you purchase additional minutes.
The advantage to this type of phone is obvious: You'll never be unpleasantly surprised with a huge phone bill because your kid decided to send 10,000 text messages one month, or talk for hours on end during another. You're also not locked into a long-term contract, in case you decide to take away your child's phone privileges. But the minutes may be more expensive than those in a long-term contract. For example, as of December 2011, purchasing 30 minutes of chat time on a T-Mobile prepaid phone could cost $10, or about 33 cents per minute. And typically, you're given a set amount of time, often 90 days, to use the minutes before they expire.
Another type of prepaid cell phone is a disposable phone. These are generally stripped-down phones without features like cameras or Web browsers -- they simply come loaded with a set number of minutes. When the minutes are gone, you toss the phone. Some disposable phones do allow you to add more minutes if you'd like, but the process can be a bit complicated, sometimes requiring you to purchase them via mail. And since disposable phones are inexpensive (about $20), you might be better off just buying another one. Disposable phones aren't always easy to find, however, and you may be limited to purchasing them online.