Yes, I believe you can. Other than my time, I've not invested a single cent into buying Steem or SBD, since I started ~6 months ago.
Continue creating content and courting followers, and you'll see the improvement over a short time.
If you're good at monitoring the prices of STEEM/ETH or any other altcoin combinations, a good way is to build up some SBD (20 is a good start), and start trading between SBD and ETH whenever the market conditions are right. I made about 30% extra SBD just by transferring my SBD to ETH and back within a week, from about 60SBD to 80SBD. A little risky, but you can also set buy/sell orders in Bittrex so the trade can be automated.
Wow, you're awesome for getting this far without investing. And you just gave me an awesome tips. It never occurred to me that we could make profits by trading between coins. lol.