People need to be very careful with "return policy" Apple vs. ATT/Verizon/Sprint when it involves 2 year contracts (aka, you are paying the $199 price instead of the full $650 price).
1. Pay full price (Apple Store), 30 day return policy no restocking fee
2. Pay subsidized price, you got 14 days to return the device or else you are "locked" into new 2 year contract with ATT/Verizon/Sprint
3. If you pay subsidized phone and want to return it after 14 days, you may be screwed. Cause carriers will not let you have another upgrade. You may "exchange" the iPhone for another phone. But with Apple retail store, you don't have many choices to exchange it for except another iphone.
4. New lines will incur non refundable activation fee after 3 days even if phone is returned
5. Upgraded lines where phone is returned will have your upgrade fee refunded. If they don't, than it's easily correctable by calling customer service.
Bottom line to avoid confusion. If buying under contract, return phone within 14 days to keep it on the safe side. If buying full price, you got 30 days to return it from Apple retail store or online.