https://www.monoprice.com/product?p_id=15365Unsurprisingly it's out of stock at the moment.
Pretty cool though that these are getting so cheap, seems like we should already have a service where a company owns a big, fast, industrial-sized 3D printer and you can order things like printed bookshelves, tables, chairs, etc. to your exact specifications - like a shelving unit that fits exactly in the space you've got, or one that's exactly the right size to hold NES carts or Genesis carts, or whatever - with no overhang or room for dust to gather, and so on.