[saintforlife]

How much does it cost to unlock the phone to make it work on AT&T? Will I get LTE speeds on the phone with an AT&T SIM? The phone will be used in the SF Bay Area btw.

Also if I buy a used Q10 from somebody on Craigslist, how do I check its authenticity? What kind of checks can I do to make sure I am not getting cheated? I am a BB noob, so please help me out.

[raino]

Yes, it will get LTE on AT&T, as well as HSPA+, 3G, 2G, etc. See here.

As for making sure you're not getting ripped off, you can start off by checking the IMEI here, but with the new Simple Choice plans, this isn't enough to guarantee you won't end up with a blacklisted phone if the seller (i.e. the original buyer of the phone) stops making payments to TMO down the line. So the way to go about protecting yourself would be to take the seller to a TMO store and pay the phone off then and there (and do another IMEI check there if you want to.)