You can offer yourself as a freelancer to earn crypto's (bitcoin, ethereum and other altcoins) depending on your skill set. Just look to the people who have been posting on Services and Marketplace (Altcoins) and gets paid according to their contact/verbal agreement.

The thing is you are just going to get paid with crypto's but the way of exchanging your service and any kind of legal goods are just the same. You just need to be more creative on what your niche is.