Have the new iPhone 6...What is involved to "unlock" my iPhone 5 prior to selling it to maybe get a higher asking price?
I'm not sure what country you are in and the process differs from country to country I would imagine.
In the UK, you can call your carrier and ask them to unlock the device and most of them will do it for free if you are on a contract with them. If not, they may charge a nominal amount o unlock the device. I'm sure a number of other countries will do the same.
In other countries that don't have this process, I think there are a number of extortionately priced websites that can do this for you but personally I wouldn't trust one of these sites as far as I could comfortably spit a Buick.