This article is interesting if you ever wondered why people people buy and sell gift cards.

Home Depot is an interesting case. Many builders and contractors in the U.S. will purchase inputs to their trade, such as e.g. lumber or plumbing fixtures or similar, from Home Depot at retail prices. They might need thousands of dollars of material to do a job, and they might have an agreement with their customer (the client or the general contractor) that they invoice for “time and materials”, with inputs being reimbursed at cost or cost plus a small margin. They may need to show receipts.

Home Depot accepts Home Depot gift cards at par, and will print this on receipts. If you buy $1,000 worth of lumber, you get a receipt saying that you bought $1,000 worth of lumber. If you actually paid $940 for the gift cards that you made the purchase with, you conjure $60 of margin (worth perhaps an hour of your labor) for a few minutes of playing the gift card game.

And if you ever buy $1,000 of lumber… you probably buy an awful lot of lumber over the course of a year.