There are some different way to earn Bitcoin without investment but you need to do hard work to earn Bitcoin. To earn Bitcoin firstly join Bitcoin forum and rank up then following signature campaign and you need to hard work for that and you can get reward in return. 

I think, You can join the social bonus program or signature campaign. 

Yes, signature campaign is a great way to earn Bitcoin without investing. This is even more reliable. And if you save your earnings, then it will already work as an investment. Because now bitcoin is growing every day and soon it will be possible to receive big profit.

You cannot earn ANYTHING without investment of SOMETHING. If you do not invest your money then you must invest your time. You cannot have one without the other!

There some ways that known to me that requires no big capital or less invesment. The first is faucet. Faucet are giving few amount of bitcoin periodically. Earning here consumes a lot of time since you have to check from time to time to have bigger earnings. One faucet give few amount so you have to join multiple faucets so that you rate will be multiplied. Next is online jobs. Some website offers jobs that pays btc in the internet. Apply for it, get the task done and you'll get paid. Search for them and you may find one. The last one is the campaign. The campaign are are found in this forum. Like online jobs, campaigns gives task to its members, you must apply first and get accepted, but the task is usually posting ideas and opinions in different sections of this forum and some social networking. If you reach your quota within the time frame, you'll get paid, either right after you finished or after the campaign ends.

Yup Bitcoin is a very good investment, and I guess what he's trying to say is how to earn bitcoins without investment like ( online investments or referrals or other online things that is promising you some result if you invest some btc, or trading )
Hmmm
Work for it bro. Signature campaigns and do some altcoins and then exchange it to BTC.
Mining is another way to earn BTC. If you are thinking about faucets years ago that is giving BTC then you can't find some profitable faucets nowadays. BTC is popular and quite expensive nowadays. You will need to invest your time and knowledge in order to earn some.

First you must know the things you're really good at or learn a skill that will help you do non physical work like writing. Writing gives you many opportunities since many companies are looking for writers to promote their product and services. It is not a simple skill to acquire but the rewards are satisfying. Learning how to write surely takes some time but you can do other jobs like joining social media campaigns while learning how to write.
there is no shortcut in earning money if you don't invest so the best you can do for now learn how things around here and post daily  (must be constructive and on topic) to increase your rank so you can join signature campaigns and earn money.

 Keep an eye out for bitcoin poker promotions and free rolls. For the past few years every time I've needed a new start up stack, I've always seem to be successful with these types of  poker room and casino bonuses. Well I doubt you're going to find many ways to get the coin for free, because in most folks lives time = money.

you can join bounty, any bounty. signature, social, blog and article, translate. or you can looking for airdrop. many ico alocate their coin for airdrop to attract most people. there are good way to get bitcoin withput investment.
and you can be trader, if you earn from ico before, you can trade it to multiple your coin

yes i agree time is really precious in bitcoin we  can really gain through signature campaign .with the single vacant time of the day.