Why shaftshift and changelly alone mate. There are n number of trading and exchanges available in online bro, you will be able to get the trade faster with all the exchange if you go with the same price you are seeing the trading site.
If you want to get the more cost than the amount you see on the trading site then only you need to wait for the price to reach or someone to accept the trading you have opened. This is it so do not worry about any exchange.