Many cell phone service providers offer unlimited call and data plans across a wide spectrum of price points. The details greatly vary between each provider, so one must research what each has to offer and find the one that fits their needs best.
The four largest major providers, AT&T, Verizon, T-Mobile and Sprint, each has their own version of an unlimited plan. Many discount providers, such as Cricket, Boost and MetroPC, use a flat fee format. These discount providers typically use one of the four major's cell towers, so it is important to check if that particular company providing the tower service has good coverage in your area.