Affiliate marketing is basically getting a code from a company, pasting it into an advertisement and receiving money, when you make a sale. That’s the basics. The depth comes in when you try to use PPC and they won’t let you advertise your affiliate link. Keep in mind I only use PPC for split testing things, in the beginning. You can function with out a web site although it is better, when you have your own for tracking purposes.

The best advertising is free advertising. I suggest article marketing and forum marketing. It's a big ocean as one person has already replied. You'll need to research and make tests. Don't spend a lot of money because that’s not needed. You basically advertise your link one way or another.

In its simplest form, affiliate marketing is getting paid for selling other people's products.
It can be rahter lucrative if done well and can also be fun.
But the biggest mistake I see newbie affiliate marketers make is not building a list.
Those who make serious moeny with this form of business, do so by gathering a following
(the people on their list who know them and trust them) and they market to these people.
simply advertising your affilate link which leads to a generic sales page is ineffective, because most people wont buy right away. So for all you effort, you will allow say 90% of your traffic to leave the site, never to be seen again.
Far better to give them something good for free in exchange for their contact details, then market to them over time.
I have heard of affiliate marketers making say $28,000 in four week even though they only have a few thousand people on their list. And they do this over and over again.
So, by all means affiliate market, BUT FIND OUT HOW TO BUILD YOUR LIST.

Affiliate marketing is really a big business. If you know how to work on it effectively, you can make the most money online.

Affiliate Marketing Is A Great Way To Start Making Money Online. It is a revenue sharing partnership between a web merchant and one or more affiliates. The affiliate is paid a commission for referring clicks, leads or most often sales to the merchant.

Make sure you do your research. You want a good, high converting product or service. Make sure the offer gets plenty of traffic.

Affiliate maketing need be paid and also many people do ,but it is also a big challenge if there are too many .Try your best to do if you have money on it.