There are many ways to earn money online like
Affiliates
Sign up to become an affiliate for other businesses on the net and you have to do is refer your customers to these sites. Once one of your referrals makes a purchase, you will receive a small payment. With some of the affiliate programs the fee is quite large. Sore programs are Commission Junction, LinkShare, ShareaSale, Clickbank, Amazon and more.
Selling Ad Space
You could sell ad space if you have a site that has high traffic.
Selling Subscriptions to Your Newsletter
If you have a newsletter that has high demand information, you could charge for your newsletter.
Selling Ad Space in Your Newsletter
Sell ad space in your newsletter. Same drill as with ad space on your website. Just put a box on your newsletter with a note inside it that says "Your Ad Could Go Here"
Selling E-Books
Do you know something about your experience or hobby that you know people would pay to learn as well? Then sell it in an e-book. That a great nice to make a little extra money.
Consulting - Offer your services
Provide online consulting service online this way you can make money online.
Writing articles:
You can write articles in different websites and they will pay for it for writing articles on their websites Sometimes that pay per article basis or sometime per impression it depends..
Online Survey
There are some website they pay for online survey or online product or reviewing reviewing.