These are really great things to look at before taking that trading leap! I say a leap because there are chances of almost losing everything.
In one of the points you mentioned free trial,there is this new Exchange that is offering zerofees trading until 1 st October,you can check it out!
You can get more info from this tutorila iw rote of how to convert Steem from your Steemit account to btc in the Exchange!
https://steemit.com/tradeio/@jaraumoses/gudnzmt-the-easy-step-by-step-guide-on-how-to-deposit-bitcoin-to-trade-io-exchange-from-steemit-images-included