I'm using cryptocompare to monitor my holdings. You just create an account and enter which cryptos you bought and the price you paid. Then it shows you a report that is updated in real time. The exchange I use it Bittrex. It's easy to transfer Steem into it, but you can't buy Bitcoin through it directly. I bought some Bitcoin on Coinbase and then transferred it to my Bittrex account. I'll probably have to do something like that when it's time to sell. I paid a $13 fee to buy $500 worth of Bitcoin through Coinbase.