There are a lot of ways on how you can earn Bitcoins. You might not need to invest your hard earned money but you will definitely have to invest your TIME and patience. There are those who do bitcoin mining. Some relies on advertisements viewing and captchas but it is time consuming and the earning is super low. As far as I know, signature campaigns offer a lot of profit than any of those I've mentioned. Once you're earning from the campaign I suggest that you put a little portion of it in investing. But be wise enough to know when to put in your money and when to withdraw especially now that the value of btc is a little unpredictable. Good luck!
I absolutely agree to that, there are many ways to earn bitcoin without any investment. In addition to that, some people gain bitcoin in faucet even though it took time to wait. Some people and bitcoin users gain their bitcoin in joining signature campaign in bitcoin forum. Lastly, joining in signature campaign is the best way to earn bitcoin and it is very effective.