as a counterargument, i think you can definitely buy old gear online. so long as you do your due diligence, it can be a great way to save some money. i stalked/loitered craigslist and fb marketplace for a couple of weeks looking for a decommissioned thinkpad and bagged a $150 470s. fortunately for me, the seller was actually a new IT shop that hadn’t set up an e-commerce site yet. aside from my anecdotal experience, i think the points @southerntofu@lemmy.ml make are mostly valid.

your friend might be talking about “refurbished” products. this is completely different from “used.” a “refurbished” product is one that goes through a testing/benchmark/verification process, and are thus [typically] free of defects, some even come with insurance, while “used” products may or may not be defective. you just don’t know, it’s kind of a toss up. “refurbished” products are usually resold by the manufacturers, local IT shops, or some more mainstream places like Best Buy. These obviously aren’t as cheap as “used” products, but they’re cheaper than “new” products.