These are new old stock surplus bulb sockets. The price is for a bag of 100x of these sockets. these most likely came from precision assembly company from way back when, as evidenced by the labels on the boxes (see picture). 

Our Stock number 4392

We're a surplus store, and we aren't experts with most of this stuff.  So, we don't make any guarantees beyond what's stated in the listing & pictures.
Feel free to contact us with any questions!

DF