This isnt quite accurate. You can get any GSM phone with the correct frequency compatability to work with TMobile USA. For instance my phone is one that was not sold by TMobile. That is what is meant by an unlocked phone. However, as stated above, if you want a discount from TMobile you need to get a TMobile phone. There may be a way around that as well. Some dealers will sell unlocked phones and give you a discount for signing a new account with TMobile. Im not sure how the new changes with TMobiles upgrade policy affects this.