Helium is one of the revenue sharing sites that I have signed up for and have done some writing for. One of the great things about Helium is that you can get an upfront payment if the article you write is one of the first five on any particular topic. If you are the first article, you get an extra bonus as well. How much you get on the upfront depends on how many stars you have for writing, but you can earn up to $2.50 each. The zero article bonus is a dollar per article. This means you could earn up to $3.50 just to submit an article. Beyond this, you are able to earn money when people view your article.
Helium pays once they owe you $25. They do only payout twice a month, so you will want to make sure you pay attention to the various deadlines to make sure your work is submitted in time to get paid when you want to be.
Please email me if you decide to sign up, as I can get a referral credit