We made these little aluminum plates at one shop, a heat sink of some sort for electronics, about 2"x 2". After we machined them we had to send them out to get them anodized. One edge needed to remain naked aluminum.
The plating shop said they had to mask that one edge, to ensure it was done properly. The whole process was something like $6/plate with the masking.
It was like $0.25 per plate without the masking. We just had the whole things plated then did a finish cut of 0.001" to remove the anodizing off that one edge...took more time to mount it in the jig than to cut it.
I bet Nemo is masking that off, hence the price.
Jon