An interesting topic for reflection. There are several options for earning BTC.
1. Bitwage - the international system of transfer of wages. It converts your salary into bitcoins, or other crypto-currencies. This can be done by transferring to your employer the bank account number received from Bitwage. The company sends a custom bitcoins a day after making a deposit.
https://www.bitwage.com/2. Freelancing
As I understand freelancers themselves set the price for their services.
Here are a few services:
https://www.xbtfreelancer.com/https://www.cryptogrind.com/https://coinality.com/http://bitgigs.com/3. Selling of unnecessary things for bitcoins:
OpenBazaar is a fully decentralized e-commerce platform based on cryptocurrency. Users can buy and sell digital or physical goods.
Purse.io - will allow you to become a trader and sell your things for bitcoins. Here you can also earn on sale gift cards for btc.
Bitify is an online e-commerce platform that accepts bitcoins and lightcoins.
Bitcointalk - allows you to sell things on your marketplace (forum).
21 Market- a start-up bitcoin forum that created "21 Bitcoin computer". This marketplace is dedicated to API-interfaces, which are paid for by btc and can be sold or bought by anyone.
4. Bitcoin cranes (micro-work)
Such jobs, which consist of simple tasks, often offer participation in surveys, promotion of anything, advertising clicks, a CAPTCHA solution, and more.
http://btcclicks.com - click on ads, The minimum payment is 0.1 mBTC (0.1 mBTC = 0.0001BTC).
Birds is a service from Bitcoin.com, which is paid by retweets. The service sends you bitcoins directly to your address, and you receive a minimum of subscribers.
The Viral Exchange - allows you to buy and sell services to promote content on several platforms of social networks. Users can receive expensive digital currencies by performing tasks such as commenting on videos or doing retweets.
5. Creating Online Content
Steemit is a block-based platform that allows you to receive Steem's cryptocurrency for the popularity of your articles. This is an automated payment with a block of Intelte, which pays Stem's capacities on the basis of "likes" of other users. The platform also allows you to earn money on content management. Altcoins can be turned into bitcoins in any online exchange.