Solved! IPhone with $10 data plan?

[wolfseeker2828]

So, here's the deal. I'm currently on a family data plan, and I have unlimited data for $10 a month. My mother refuses to use her upgrade, but I just recently saw she could get a used iPhone for only $19. Here's my master plan, tell me if this will work:

1. Buy the iPhone.
2. Steal the iPhone from my mom, who doesn't want to switch phones anyways.
3. Call AT&T and cancel the iPhone data plan for my mom.
4. Use the SIM card for my phone in the iPhone

Two questions: firstly, would I be able to cancel my mom's iPhone data plan without returning the phone, and secondly, would I be able to use my $10 data plan on the iPhone?

 

[redinsanemetroid]

To my best of my knowledge:
1. No, you can not cancel the iPhone's data plan without incurring an early termination fee if you're in a contract. Also, you can not buy an iPhone from AT&T without purchasing a data plan with it.
2. No, you can not use your $10 data plan with the iPhone as the iPhone has its own specific tiered data plan (the $15/month and the $25/month plans).