For the first and very important, we must know if business at cryptocurrency is very risky. So if you want buy some altcoin, you can look at the website, there's a lot of market exchange you can get in. But for advice, please read carefully and before that, please looking for the information about that exchange site. In my experience, you can go to bittrex,poloniex,binance as long as i know they are good at security and service.