My dear (pretend) friend Elisabeth Hasselback turned me onto this site today: https://www.wirelessamberalerts.org/index.jsp
It's a free service and you will not be charged by your cell provider. When signing up for the service you enter upto 5 zip codes. When a child is missing from any of these areas a text message will be sent to subscribers. Studies show that the first 36 hours are the most crucial in finding a missing child. The more people reached, the better the chances of recovering the child!!