If you dont want to do investments and use your money from your pocket, joining bounty campaigns is another way to make money. But of course you need to invest your time and your effort. It is not given free of course, we need to work for that.
Knowledge is very important for you to have profit without investing money, bounty campaign is a one of great source of profit but of course if you don't know how to done it you will be not qualified for the payment. Also don't expect to make easy money without working hard on it, just keep on working and money will come for your.