Luno Popular. At the same time, decentralized exchanges are still in the development phase, which means that they are not very friendly to use. Please visit Luno for its exact pricing terms. Bittrex is one of the world’s largest 10 cryptocurrency exchanges. Buy Bitcoin Worldwide receives compensation with respect to its referrals for out-bound crypto exchanges and crypto wallet websites. Some examples of poor UI that stand out in the space are Poloniex and Bittrex, which both command extremely high levels of volume in the altcoin markets.