IMEI check
Find out what the phone is — and whether it is reported lost or stolen — before you buy it. Checking the number and naming the model is free and unlimited.
Dial *#06# on the phone and the IMEI appears on screen.
Show everything the network returned
Dual-SIM phone? Check IMEI 1.
IMEI 2 can return clean on a device whose IMEI 1 is blocked.