Doing transaction without miner fee will be impossible thing to happen but paying low fee might take your transaction to a very long time of wait. Because miners perspective that if you pay a large fee, that transaction might be urgent or an important one that's is why you are paying a large quantity of transaction fee. Yes your money must return to your account upon pulling out your money from the pool. But if you want to assure that your transaction will be process, pay the right amount and take a lot of patience upon waiting.