I have been looking around the web for a few weeks now trying to figure out how to unlock my AT&T LG Prime phone. I often travel to Canada, but the AT&T GoPhone prepaid service doesn't work in Canada. Since I already have a nice cell phone, I wanted to unlock the phone for use with Canadian prepaid networks.
Searching Google for "unlock LG prime phone" is like dropping into an abyss of nearly identical commercial services. I started shopping around, and found a bunch of places that offer cell phone unlock codes (I think the cheapest I found was around 10$). I didn't really want to spend any money on the unlock codes, but my local Radio Shack wasn't able to unlock the phone for me.
Today I went into a local AT&T wireless store, and asked them about it. It turns out to be extremely simple: I called 611, spoke to an AT&T customer service representative, and she gave me the unlock code. It was fast, and the representative was really helpful.
I have included a video below of someone else unlocking their phone. Remember: you can get the unlock code for free from AT&T, you don't need to buy it online.
Also: Some people on YouTube don't seem to realize that the code shown in the video will not work for their phone. The code is different for every phone, you will need to call AT&T for your own phone!
Edit: Lots of people seem to be looking for the following sentence: ' "invalid sim network lock" lg prime.' This is an error message that appears when you put a non-AT&T SIM card into the LG prime. It just means that the phone is rejecting the SIM card because the phone is locked to the AT&T network. If you want to use the phone with another network, just call AT&T and ask them for the unlock code.