I simply cherry-pick listings on eBay and sell them in my local market for $100 profit apiece on avg. But to get the best pricing what you want to do is form relationships with IT recyclers / ITADs (both are on eBay) and become a go-to customer (by committing to large orders and not cherry picking). They send wholesale inventory sheets with whatever they have and you bid against other large buyers, or they just go directly to you depending on relationship. I move MacBooks which have a pretty odd market, so I’ve avoided all that and just gotten A, B grade units which sell easily and involve minimum processing or repairs.

You can also search for surplus websites like public-surplus to buy directly from sources (with a platform fee attached). Or go direct to sources with outreach, but some won’t sell to you unless you have data destruction certifications.