okay im planning on buying a sidekick for myself but i have at&t i know if i unlock it i will only have the phone and texting but im gunna go to the the tmobile store and buy the sidekick but it says they will unlock it for me after 90 days except for people who pay for the phone full price (which is what im gunna do) but before i go there and waste my time willl they even sell it to me if i dont have tmobile and if they do sell it to me will they unlock it for me?