i do not think it is possible without trade. if you are good and experienced in trade maybe you will earn enough money. But first of all, you need good capital to buy BTC.
I completely agree - to start earning money, you'll need money.
Starting with low capital and get too big earning is possible but it will require a lot of patience.
But if you have the money, do a really comprehensive research prior to any investment.
And most importantly - good luck!