Getting the Iphone 5 at Apple store instead of Sprint

So i just have a quick question to ask, i haven't been to the phone store for a long time so i'm kind of behind with the mobile world! So i'm current have a family plan with my mom and dad a very cheap old plan so i'm paying 10 dollars right now, so now i want to cancel my phone in my parents plan to move to the data plan to get the iphone 5, but my mom want to buy the phone at apple store instead of sprint store, if i get mine at sprint i can cancel my 10 dollars plan in sprint and sign up a data plan there and transfer my number over to iphone 5, i was just wondering can apple cancel my 10 dollars plan and sign me up to a new data plan?

Added (1). And it is a good idea to go to the apple store early on the 22nd not the 21st when its release? Bc i heard the line for iphone can be long

Added (2). Sorry the 23rd i mean

I'm not what your 10 dollar plan is
but wherever you get the phone, You will be forced into getting a data plan
so yes, apple will be able to change it

But, if you haven't preordered/reserved your iphone yet, the only way you can get one is to line up really early on the 21st. If you are able to go early enough, you may get one of the unreserved phones
But if you go on the 22nd, there's no chance you will get the iphone 5

So either go Really early on the 21st, or don't expect to get it until october