Bittrex fee for sending NEO is not large, 0.01 or 0.025 NEO per transaction, can't remember exactly, you can check. For example, if fee is 0.025 NEO and you want to transfer 100 NEO, the number you are typing in withdrawal field should be 100.025, and you will get 100 NEO in your wallet or other exchange, wherever you are sending NEO. I recomend NEO GUI wallet, it's pc wallet, you can download it from neo.org