It can affect pricing. For example you link to Amazon because you get an affiliate kick back as opposed to linking a different vendor that might charge less and not give a kickback. That’s just an example, of course, Amazon may also offer the best price on any individual item.
The material relationship between Boing Boing and vendors affects the choices Boing Boing makes over what and how to write and who to link to over what they would do if there was no affiliate relationship - which is why it is important to make clear and conspicuous disclosures to consumers, as per the FTC guidelines.
