It is very easy to join an affiliate program. You can start advertising the same day as they give you your affiliate web page link. That is literally all there is to it as far as planting the seed and starting out. The program provides the product or service that you can earn money from if you are able to sell it.
So far you have invested nothing – no time, no effort (yet) and the only money you have spent so far is the membership dues if applicable. You are getting a very fair deal in most cases if there are no contracts other than month-to-month (no contract should be a requirement when determining which program you want to start out with).
Just factor in what you would have had to spend to start a business without being able to join an affiliate program. Consider the cost of market research and product development, programming, website developmen