On a voluntary, part-time basis, I used to run a second-hand store for my church. A good part of our sales were to second-hand book stores, second-hand furnitur

On a voluntary, part-time basis, I used to run a second-hand store for my church. A good part of our sales were to second-hand book stores, second-hand furniture stores, second-hand CD stores, and second-hand (read: retro/vintage) clothing stores. I loved these customers - they came reliably and almost always bought something. They didn't haggle, and didn't ask for credit or for things to be held for them. The guy who wrote this Slate article is doing a similar thing - being a regular purchasing customer of the places he frequents.