Can i just get an unlocked t mobile phone from ebay and put my SIM card it in?

My Nokia from T-Mobile is old and is messing up. I want a new one but I don't want to spend hundreds or wait a year for the contract to be up. Can I just buy a T-Mobile phone from ebay that says it's unlocked and put in my SIM card?Can i just get an unlocked t mobile phone from ebay and put my SIM card it in?If the phone that your gonna purchase is from T-Mobile it doesn't need to be unlockedCan i just get an unlocked t mobile phone from ebay and put my SIM card it in?yes if that sim card is already activeCan i just get an unlocked t mobile phone from ebay and put my SIM card it in?unlock t-mobile code: http://gsmunlocklabs.com/tmobile-network鈥?/a>