It's generic one I found on amazon.com , I don't think it had a brand name at all tho the Cowboy Studio one on amazon looks like its doppelgänger. Currently $23 on amazon. It came with 2 mounting plates, I originally got it for my Nikon DSLR. The mounting plates have 4 pieces of double sided tape on them, essentially clean LCD, peel off the backing and stick on. The loupe has magnets in it that then attach rather nicely to the plate. Sure it's not as nice as a Zacuto Z finder but it's also 1/10 the price too. Works quite well. Gives that nice 3 point hold and allows you to see LCD even in bright sunlight.
CowboyStudio CA0602 2.8x DSLR LCD Screen Viewfinder for Canon EOS 500D,550D,600D and 60D Digital SLR Cameras - Black http://amzn.com/B005EM6G7U
Not surprised. Ebay is not always the best deal. Reason... there are a lot of re-sellers on ebay that count on people not researching the internet well for best price. I know... I used to be one of them. I used to go buy motorcycle parts from various websites on the net and resell on ebay for a profit. You'd be surprised how often something that looks like a deal on ebay could be bought cheaper from an online retailer or discounter.