Credits are what Universal Alert uses to send out phone calls and text messages.  Each call and each text message sent use one credit.  A phone call and text message sent to the same person uses two credits.  A standard subscriptions comes with 500 free credits every month, and additional credits can be purchase for just 10 cents each at any time and in any increment. 

Here are some examples of how credits work to help make it a little easier to understand:

You send a message to 20 people via text only = 20 credits
You send a message to 20 people via phone only, 10 people's phones ring unanswered = 10 credits
You send a message to 20 people via phone and text, all people pick up the phone = 40 credits
You send a message to 20 people via phone, text and email, all people pick up the phone = 40 credits