Yeah I'm on that site. Would you be able to help me answer something?
Can I buy a phone online at full price and then change it to AT&T Next when I go into the store to pick it up? Also is it true you can't buy through AT&T next in store?
If by "buying" a phone you meant reservation & pick-up - I believe once the phone is reserved it's yours. When you go in store you can choose to purchase it in whatever way you're eligible for.
But if you meant placing an actual order through apple.com, then it's finalized. Your card is charged when phone is shipped.