Hoodman H-RAV Universal Right Angle Finder. This is cased and in very good condition. It comes with finder adapters for Canon 18mm, 19mm, and also one called "universal" - these slip over the slotted mounting flange on SLR finder windows. I seem to recall using this briefly on a Canon EOS camera of some sort that I once owned, but I really have no idea what model Canon cameras this is designed to work with, so please understand this or do some research before buying.
Price: $30 plus shipping
Price: $30 plus shipping