system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What is cellphone unlocking? Why is this issue all of a sudden so pertinent?
gpt
When you buy a cheap cell phone ( with a 1 or 2 year contract ) you're only paying a fraction of the phone's cost in advance. The rest of the cost is included in your monthly payments.
The carrier who sponsors your phone wants to keep you as a customer so they 'lock' the phone so it won't take a SIM card from another carrier.
So when the term of your contract runs out you'll be forced to stay with your current carrier or you will have to get a new phone.

It's been legal to remove this lock from your phone for quite some time. But recent legislation in the united states has made it illegal to remove these locks. Which is kind of strange. Because once your contract is up you've paid for you phone in full and it should be yours to do with as you please.