Apple has a 14 day return/exchange period for purchases. If returning for a refund and the box has been opened you will be charged a restocking fee (on computers, not accessories) unless it's defective and it's blatantly obvious it's defective and even then they will offer an exchange first. If you've opened it and just want to return it "just because" then you will be charged a restocking fee of 10% of the price.