:+)...Affiliate marketing is a link Amazon offers, and pays a few pennies per buy when a consumer recommends a product; and, others buy using that link. Perhaps, you're already familiar with it; but, it's very popular on YouTube. Of course, as with anything, some people have gotten it down to a science, and actually make a living from it. However, for most it's just a few extra pennies in the coiffers.
Btw, many thanks for the up-vote...very much appreciated!
Peace.