If you are an affiliate you are trying to sell products for someone else which is paying you a procent from what you made. This is an affiliate program.
Affiliate programs work this way - someone has a product. You promote the product, he gives you a commission. You can earn if someone clicks the link for the product or when someone buys it.
An affiliate program is essentially a system whereby any individual can earn a sales commission by acting as a salesman for any business online... Simply put, an online business is selling special diet pills that are clinically proven to reduce cholesterol, weight, and fat... Their price is $150 for a 6 month supply... You build your OWN website and start talking about diet programs, the latest diet trends and the best foods to eat... then you put a text link or banner advertisement on your site.. one of the visitors to your diet website sees your text link to the special diet pills and then orders the product because of your recommendation. The customer pays $150, and you earn 50% of that or $75.... That my friend, is what an affiliate program is...
The question is too common. May be you'd better to start from google search and define the most common concepts of Affiliate Program.
You presell a product on your site, then drive traffic to the product site where they will then purchase the product, and the copmany will give you a percentage of the sale. It is a popular form of marketing becasue you dont ahve to deal with shipping, customer complaints, refunds, etc etc. My blog has an outline of how I am going about my own affiliate marketing if your interested. Troy