Gaston: very best job costo de topamax 25 mg Parents of teens may use prepaid plans to moderate minutes. "It's a great way to make sure that there are very clear limits and absolutely zero chance of overage," says Amy Storey, a spokesperson for CTIA-The Wireless Association. "Once you're done, you're cut off. You can always reload at any point, but it is an easy way for parents to keep track of their child's usage."