You can only use a cellphone if it is from MetroPCS, Because metroPCS phones are based on there network and the way there pre-paid month plan is set-up. All metropcs phones even have a special menu in the phone called "MyMetro" where you can check your balance and payment options. The only way you can get another phone to work is if you can possibly get the metroPCS software onto the other phone and it is compatible with the network, you need a cellphone hacker to do all that.