Quite a lot. I think Bittrex is 0.25%, poly between 0.15% and 0.25% depending on whether maker or taker. Binance was free now I think it's 0.10% or 0.05% if you use their token. So it's a pretty big difference.
Some people (myself included) don't like leaving to much sitting in exchanges if you're not trading it, so the best thing to do is move it to a hardware wallet. The fees for that are flat and can range from about $1 on Bittrex to next to nothing on binance depending on what coin you're moving.
