Affiliations are a good way to make money on the Internet. There are hundreds of affiliate programs available to choose from, representing many different kinds of products. The first, and probably most famous, affiliate program was Amazon.com's. The great thing about affiliate programs is that you don't need a product, or even a web site, to make money on the Internet. Many affiliate programs give you a web site to advertise, and that's really all there is to making money this way. Promote, promote, promote!
Things you should look for in an affiliate program are reporting capabilities (so you can see what sales you've made, what commissions are due you and whether they've been paid), multi-tier programs (so you can get paid commissions on the sales of affiliates that have purchased from you), and perhaps most importantly, contact information, should a question or problem arise. High commissions are a big bonus too.