One online business opportunity is called, Affiliate Marketing. This is a business that you would work for yourself, you work your own hours and all you really need is access to the internet. Basically, your job is to send potential customers to other peoples products. When a customer buys that product through your link, you will earn commission (money). Affiliate marketing is the most profitable way to make money online.
Another business opportunity is drop shipping. Have you ever seen any Ebay stores? Well Ebay stores are usually created by someone who is in the drop shipping business. If you were to get into the drop shipping business, you would most likely join a drop shipping distributor and get products from them. Using a drop shipping distributor allows you sell products without actually having physical inventory and when they are sold, the distributor send them out for you. With the business, you are able to set your own prices so that you make a profit with each sale.
Paid Surveys. I feel that this isn't exactly a business, but it is a way to make money. If your only looking to make a little bit of extra money every week. Paid surveys are the way to go. I do not suggest trying to make a living with surveys. It just will not work. It's boring and not always guaranteed you will get enough surveys to meet your needs.