A prepaid SIM card is a mobile subscription that allows you to prepay for a set amount of mobile data, talk time minutes, and text messages. It allows you to make calls, send text messages, and use data on your mobile device without a long-term contract or monthly bill. Unlike postpaid SIM cards, prepaid SIM cards do not require credit checks, long-term commitments, or activation fees. A prepaid SIM card is purchased for a set amount that acts as a credit balance with the provider. As talk time and other services are used, the company makes charges against the credit amount. If the credit drops to zero, service is immediately discontinued. The card must be reloaded with additional credit in order for service to continue or to be restored. Prepaid SIM cards are popular among travelers who want to avoid roaming charges and among people who want to control their mobile expenses.