Amazon Affiliate Links
I know of a guy who started out as a handyman. He then took that idea as a handyman and started his own blog to teach people how to fix things themselves through blogging and video tutorial. At the end of every post or video, he would tell you what tool he used to get the job done and would provide a link directly to Amazon for you to purchase that product.
However, he also signed up for a free Amazon Affiliate Account. Every time someone clicks on his link and buys ANYTHING on Amazon, he gets a commission! Think about this: Amazon pays him for the tool he recommended and also for anything else they Add To Cart.