There are other types of handsets that will not come accompanied by any sim card, the tricky part is the handset will work with the first sim card used on it by the owner. It means you have to unlock your handset if you have to use another sim network.

This blog is about unlocking Samsung mobile by sim gsm network unlock pin. Step by step instructions for Samsung android mobile unlocking through service mode without imei generated unlock codes. Various techniques of unlocking Samsung mobile.