A:AnswerThe AT&T phone will be carrier-locked. AT&T's unlock policy is approx like this:
After 60 days the phone can be unlocked. This doesn't happen automatically; they have a website for unlock requests.
This policy isn't the worst one out there, by far. Boost Mobile's is far worse (1 year).
A:AnswerThe cost of the plan is not included in the amount financed for 30 months. A typical plan is $75 a month. Only the price of the phone is financed for 30 months.
A:AnswerActually, I checked with Best Buy. They are not offering the iPhone 12 mini unlocked right now. You have to select a carrier. Not sure why on this model -- I have purchased unlocked phones from Best Buy in the past. In the past when I have purchased an unlocked phone, it was not more expensive, but carriers will normally offer an interest free installment plan that lets you spread the cost of the purchase out over 24-30 months.