for unlocking you need a cable type PCB093LBEC remove the rubber part in the box, and switch it to mode DL then go to www.UnlockSamsungOnline.nl/eng and download the client login, select X450 and correct comport.. press unlock button then wait for 15 seconds, and your phone is unlocked
no your phone cannot be unblocked by any free code, there is an option to get the code but it will cost 20 euro, the cheapest way for online unlocking is the http://www.UnlockSamsungOnline.nl service if you still want to get a code you can try http://www.ust-online.com you can also try to get the code from your provider