To make sure your BlackBerry device is brand new and never been used before, you must check its data and voice usage. Go to Options –> Status –> on status page, type ‘BUYR’ with your QWERTY keypad. Two new rows of information will appear: Data Usage and Voice Usage. Both value for this new information must zero. If not, that particular device you are checking might already been used before, either data use or voice use.
Another thing you might consider in buying BlackBerry device is whether you can use your SIM card from Telco provider of your choosing. For instance, you want to buy a TIM Bold 9000 and you want to use TSEL network, you have to know that TIM Bold 9000 already unlocked. Go to Options –> Advanced Options –> SIM Card –> on SIM Card page, type ‘MEPD’. Five new rows of information will appear: SIM, Network, Network Subset, Service Provider, and Corporate. If all value of these new information are “Disabled”, that means this particular BlackBerry is unlocked and you can use it with your network.