Because MetroPCS doesn't have contract plans, it typically only offers discounts for new activations, so upgrading a MetroPCS phone means buying a phone outright and activating it. Customers can buy phones at MetroPCS stores or the company's website, but T-Mobile and unbranded phones often work as well.
MetroPCS is owned by T-Mobile, so phones are compatible between the two networks. Unlocked phones that use GSM technology might work as well, but it's important to check which frequency bands the phone supports. Because MetroPCS uses SIM cards for activating phones, customers can often remove the SIM card from their old phone and place it in their new phone. MetroPCS offers online activation service.