Don't forget online school auctions

You get a chance to see the actual items a few days before the auction. They give you a day to preview. You know exactly what you are buying. Most buyers do not go very high, they have to double or triple their money in order to make good profits.
I bought a 15 feet library book shelf 4 feet high for $250, the warehouse guy told me that the school district had bought that for $3500 a couple of years ago. I put it in my living room in a L shape. Shelves are deep since it was for double sided books.
I sell on ebay and Amazon. And have made some money nice hobby. Kept a lot of stuff.