Affiliate programs are the number one most popular way to market on the Internet. There are thousands of affiliate and reseller programs covering everything from books to baseball bats. I make a better bat, you put my banner on your site, and if someone buys a bat after coming through your link, I pay you 25 percent of the selling price. Killer idea, right? That one sale won't be enough money to pay the mortgage or even enough to take your kid to the movies. And to make matters worse, how man.