Although a person can unlock a cell phone by himself using a program from the internet, it would be easier to buy a phone that is already unlocked. More people prefer the latter as it is more convenient than having to buy a locked mobile phone, and having to pay a shop, or a website, to do some blackberry unlocking (if your phone is a blackberry). Trying to unlock a cell phone all by yourself might also be a little risky, especially when it's your first time doing so.