The "boots" item feels less true, because expensive doesn't seem to be as correlated with "good quality" as it used to. But the general statement still very much stands.
Things like financial products that charge higher interest rates to poorer people, or services that offer discounts for paying annually rather than monthly are great examples of this. And less direct things, like being able to drive to cheaper shops and buy in bulk, or being able to do preventative maintenance to avoid a cheap fix turning into an expensive one.
It can still apply to individual items, as long as you're careful about what you buy and do your research to make sure you're actually buying high quality boots, and not just cheap ones with an expensive logo on the side.