Always check the price...
I managed to lose the eyecup for my camera - it is the bit that fits on the viewfinder. Its a bit of plastic and slightly cushioned surround.
I did not actually look at the price, but as I needed it I paid it anyway even when they rang up $75 (about £50).
I just checked, and as I suspected, in the UK you are looking under £10 for this bit of plastic even with a Canon logo on it!