Your best bet is probably joining an affiliate network. An affiliate network will help you set up an affiliate program and work to recruit affiliates for you. You'll have to fill out an application describing the nature of your business and your Web site. You'll also have to agree to the terms of the affiliate network and make a number of deposits. These will probably include a one time charge for becoming a member of the network as well as a deposit to be used to pay your affiliates. Some affiliate networks also charge a yearly fee for their services.
In return, the affiliate network will help you set everything up, keep track of all the activity in your affiliate program, issue your affiliates checks and distribute your links to appropriate affiliates. They will give you the option of reviewing prospective affiliates, or you can choose to accept all interested affiliates automatically.
The alternative to acquiring affiliates, maintaining an affiliate program yourself, is significantly more complicated. Among other things, you would have to screen and recruit all affiliates yourself, purchase and maintain some sort of tracking technology, instruct your affiliates on how to set up links to your site, set up an accounting system for paying all of your affiliates and set up a help line to assist all your affiliates.
There are a number of traffic-tracking software applications that will probably cost between USD100 and USD500, significantly less than joining an affiliate network. Another option is to sign on to a company that keeps track of the traffic involved in your affiliate program by running it through their site on the way to yours. Using one of these companies costs about the same as tracking software, and they also only assist you in tracking.