Apple is now refusing cash for the purchase of iPhones. They now require a credit card for purchase, and the limit for the number of iPhones you can purchase is now two. Apple stopped accepting Apple Store gift cards for redemption. The move is legal -- they're not obligated to sell you anything, and they can impose the extra restrictions.
This definitely isn't the most customer-friendly policy I've ever seen; most kids aren't going to have their own credit card. If Apple wants to obsessively manage their supply of iPhones for the holiday season, no amount of bad press is going to change their mind.