Simply put, prepaid cell phones are mobile phones where you buy the service for them before you use them. Essentially, you buy credit to use a provider’s network so you can avoid charges and recurring bills. Such a cheap cell phone plan are often defined as a “pay-as-you-go” service.
With most cellular service providers, you can add credit to your prepaid cellular phone account any time to top up your account. This can often be done by either purchasing a prepaid card in a retail store or using your credit card to buy the additional credit directly through your cell phone or cellular provider.
Note that most prepaid cell phone solutions utilize SS7 (signaling system seven) out-of-band signaling.
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