I was pretty lucky to be in a department that was one of the SDSS members. The metal plates they had were only used a few times since each one was unique to the field it was designed for. After they were done with them they sold them to some of us grad students for $20 (the price they would have gotten as scrap). When I move into a house I'm going to mount mine on a wall so I have a little piece if scientific history to look at. :)
One thing to add, too, is that the plates are pretty big! Each one is about three feet across and maybe 1/8 inch thick!
It's really a technological marvel, and some truly brilliant engineers and scientists were working on it. I'm intensely gratified that the survey has been such a smashing success; they all deserved it.
The part I was always most impressed with was they way they took the spectra. As mentioned in the article, the survey was twofold: the image survey over the vast swaths of the sky and somewhere around 2,000,000 spectra taken of distant objects.
Every single one of those spectra was taken by use of a fiber optic cable at the focus point of the telescope. They would take a metal plate, drill holes in it where the objects would appear, and plug the holes by hand with the cables: http://blog.sdss.org/wp-content/uploads/2014/05/twitter5.jpg
2 million times!