Bitmex gives every liquidity maker a rebate on their trading fee whenever they bring in liquidity to the market, the market takers aren't given these kind of opportunity but the exchange offers them a low fee depending on the coin being traded. Bitmex is an awesome exchange, I enjoy their service a lot because they are cost effective and fast, I don't have to stay all day long waiting for my commands or request to be granted cause the exchange has a very good API and support team is also amazing. Bitmex offers an affiliate program for traders to bring in their friends in to register for a trading account and earn commission from their referral's trading fee, this is a feature of Bitmex I haven't tried out but it's another good way of getting some funds on exchange. Bitmex lists just few coins, the listed coins are helpful but I believe having more new listings would be quite more better for large scale investors or traders in general.