I'm not sure about disposable phones, etc., but a warning about Northern Arizona, and southern Utah, don't know about Nevada. Verizon works the best, since cell phone towers are not as prevalent and these are rural areas, only certain services work in certain areas, i.e. Verizon works the best in northern az, but it doesn't work very well on the rez in naz. It also does not work well near Las Vegas in the rural areas there; but works fine in Las vegas