Which is the best way to do this? I have an upgrade on a line available and have already used mine to get my 3GS. Buy it at ATT Online and then sell it on for around $500-600 or Buy it at Apple Store and then sell it? I mean i will sell the phone and keep the line (will cancel date by lost phone or something) but which way should i do it? If i buy it online would i have to activate first before i say the phone is lost or stolen? thank you.