I'm surprised at the number of people who say that you can't start a business without investment. No business is going to work without investing your time into it, but I'm assuming that most people were referring to financial investment. Anyone who is setting out in business without start up funding might find the links below helpful (I'm not affiliated in any way with the sites listed); 0 to $500 / Mth from Blogging 20 Small Budget Start-Ups 23 ways for teens to make money (and maybe adults too!) 101 Ways to Make Money Online The following business forum (mine) threads might also be helpful to you; Free Ways To Make Money Online More Free Ways To Make Money Online If you look at the Buy, Sell and Trade section here on DP you will see that there is business being done all the time, by people who did not need investment to set up. For example article writing, logo design, forum posting, etc. Good luck with it.
You must invest something always. You do not need to invest money, but your time and efforts are necessary. Maybe you have to consider affiliate or dropshipping.