Possibly the shop ran into a problem selling spokes to a customer that went badly and due to a likely a hole customer all customer's pay the price.
My shop has no problem selling 1 or more spokes. We don't make a fortune replacing one spoke. Often the wheel owner loosens too many spokes, etc. and we basically have to retention and true the wheel...that can be a pain in the ass especially when usually the rim itself has a nice little warping to make trueing a real pain in the ass.
Most shops have boxes and boxes of spokes and sell so few of them. It sucks to have to buy a box of 100 spokes to replace one or several. We don't make a profit buying like that. Consider also how many types, lengths, colors, etc. of spokes are in normal use...it is insanity. But it has to be done and a good shop will do it one way or another...We just got a brand new spoke thread cutting tool...can't wait to use it.