I have compiled a list for the main money making sites available online. These are broken up into categories, with pro's and con's for each site. All sites are 100% free to join.
WRITING
HELIUM - An on line submission for articles and creative writing.
Pro's - Instant article submission, instant article acceptance.
Con's - Can't sell your articles, hard to delete an article once it has been submitted.
ASSOCIATED CONTENT - Well networked site to submit articles to.
Pro's - The media can choose to buy your content, new bonuses per page view.
Con's - Payment only available to those who live in the USA.
CONSTANT CONTENT - A site where authors can submit and webmasters can buy content for their sites.
Pro's - You can set a price at which you want to sell your article at, buyers can email requests for content.
Con's - Articles can take up to 5 days for submission.
SELLING
EBAY - Everybody knows this one, sell (almost) anything on-line.
Pro's - Auction settings, set a reserve price.
Con's - Ebay sets charges for listing your goods, illegitimate buyers.
CAFEPRESS - A place where you can start a shop for free, then upload your images to be printed and sold on various goods, can also print books and audio Cd's.
Pro's - Don't have to deal with postage and packaging, don't have to buy stock.
Con's - The basic stock is more expensive then normal.
AFFILIATE
CLICKBANK - Sell other peoples digital property online (e.g., E books)
Pro's - High commission rates (up to 75% of product value)
Con's - some products have high return rates.
COMMISSION JUNCTION - Sell other peoples products online
Pro's - Don't have to deal with posting the products.
Con's - Only paid per purchase not per click of the add.
BLOGGING
ADSENSE - Google's advertising system lets you place adds on your website.
Pro's - Pays per page view and per click, adds relevant to your site content.
Con's - High traffic site needed to make lots of income.
SURVEYS
GLOBAL TEST MARKET - Get paid to fill out surveys
Pro's - Choose which surveys you want to take
Con's - high minimum pay out rate
Watch out for any site claiming it can make you $20,000 in a week, or any site which makes you pay money to join. Trial and error is the best way to make some extra cash - see what works for you. Good Luck.