For starters, I don't buy "messed up junk" (to use your terminology here). Everything that I have bought, including single-bid chips have been of very good quality or higher. And I have also managed quite a few surprise purchases, in that they were chips that were worth much more than expected.

For example, I purchased what was listed on eBay as a $5 Castaways cancelled chip, but the image listed was of the $25 chip. What came in the mail was exactly what was pictured, the $25 version, not the $5. Another time I purchased a $25 Nugget Carson City chip at the last minute, which there were exactly zero bids on, and this was a chip in excellent condition and also was an M value according to the TCR.

When it comes to eBay, I'm very selective in the purchases I make. And yes, I do look for the bargains as well (such as the $1 La Rue chips that were offered for instant-sale at $50 each). The goal is to have a worthwhile collection, and I think I'm on track in that respect.