I've been on the lookout for a shelf to tuck behind a chair and put my printer on. I'd pretty much given up and decided to build one, mainly because the spot I needed it for was an odd size. Today, while poking around in the local thrift store, I discovered what I thought was some shelves that were perfect. When I went to pick them up, I made another discovery. They weren't shelves at all. They were very simple end tables stacked on top of each other! I got them for $2.00 apiece!
For me, the lesson of the whole experience is; remember to look at every possible way something can be used before dismissing it as unusable. I would never have thought to stack end tables to solve my shelving problem.