Do I Need To Build a Web Site?

No, you can get into affiliate marketing without the hassle and technical challenge of building a web site. And you can still make big money.
Have a look at the Google ads that appear next time you do a Google search. Sometimes its obvious the ad has been placed by an affiliate, rather than by the owner of the site that you get taken to when you click it. It could be a different style or wording, or the way it clicks through. Somebody has placed the ad to catch your attention and earn a commission if you click through and buy.
How do they do this? The answer is thoroughly explained in Chris Carpenter's Google Cash.
This approach is not for the faint hearted. The process has to be closely managed and you will have to start with some working capital to invest. You will have to buy advertising, usually with Google Adwords. How much depends on how big a business you want to build. You should start small, of course, until you master the techniques. To make sure you make a profit you will need to consider access to keyword search and performance measurement software. You will need to commit yourself to learning a systematic approach to select and promote products that sell, and keywords that get your ads seen by your target market. Get it wrong and you could lose heaps. You need someone like Chris Carpenter by your side to guide you through the minefields.
You should think about investing in advice from a few other experienced experts in this field as well. Just a few more dollars spent learning how the successful people do it could prevent you spending a much bigger amount of your cash to learn the hard way. People like:
Scott Adams, with his up to date Affiliate Adventure guide, or
Mike Delrue,with his Affiliate Money Tree 2006, which he claims is making him over $18,000 per month, or
Greg Heslin, with his Google Adwords 123.