Bitcoin arbitrage is the purchasing of bitcoins on an exchange where the rate is extremely reduced and also offering it at an exchange where the cost is fairly greater. The rates of Bitcoin differ on different exchanges, as a result of that the marketplaces are not straight connected, and also the trading quantity, on lots of exchanges, is reduced sufficiently that the rate does not get used to the typical as soon as possible.
here is a video to understand what is the Arbitrage.
if you need information about exchanges where the bitcoin price low and high difference between 150$ to 200$ feel free to ask.