Probably best to get one sent from your company, even if you have to pay for it. The only sure way to get one unlocked would be to order it from a reputable dealer like Horizon Wireless
. You could always try to pick one up from Craigslist or some other setup like that, but more times than not you'll get a dead/stolen/misrepresented one and be right back where you started from - without a working BlackBerry. Only now you'll be out whatever you paid the scammer you found on Craigslist.
You might be able to scan the forums here or on Howard Forums for a seller in NYC that has a history on the forum. That's your best bet for avoiding a scam in a private deal.
In any event, the new device will have to be activated on the corporate BES by your admin team.