When you go to launch an affiliate program, you need to budget to fund several items. First, if your company is well-established and you're just branching into the online affiliate networks, it's a good idea to hire an experienced affiliate manager to run the program for you. You'll also need to budget for the affiliate technology and the commission you will pay out. Finally, you'll need to pay someone to create the text links and banners (make sure they are well designed and effective). Your affiliate manager will track the different programs, keep tabs on the different affiliates, and make recommendations for various promotions.
Whether you're going to start your own affiliate program from scratch or sign up with a management company, it will initially be a lot of work.