ATT prices range from $25/month to $75.99 per month. The exact prices can vary depending on several factors. Unlimited Extra EL, for example, is just $40.99 per month per line when you have 4 lines, but it’s $75.99 per month for just one line. Meanwhile, when it comes to a prepaid ATT single plan, you can get service for as little as $25 per month. It’s important to carefully evaluate your data needs and budget before choosing a plan.