With c2 being quite new, as well as html5 being refined on various browsers bit by bit, most of the games I listed were released for free as direct payment options are slim. However, the majority contained ads (which is a good way to make money with your game - just don't expect large figures for your first offering) and some no doubt had sponsorship deals (which is a good way to make a lot of money, if you can figure out who to approach and how best to do so).
True Valhalla makes a regular income from his html5 games, which is large enough for him to live off. He also gives a monthly account of what he earned and how. It's well worth reading his blog here: http://www.truevalhalla.com/blog/
It's taken him a lot of work to build up a reputation, but if you're determined enough and put in the hours and do some research, you could get there as well. Just don't put all your expectations into making lots of money from your first game (currently my first game has earned 56 cents. But I learnt a lot through making it, which is the main thing at this stage)