Owing to a simple numerical misunderstanding, I bought six dozen (instead of six) of my favourite ones some years ago. It was at Music Live exhibition and they were very cheap.
Oddly enough, since then, I've never found it hard to find one.
There's one on every stringed instrument- even the violin, oddly, one on every flat surface in my music room, and several on the bedside table upstairs where I took them out of my pocket before putting my clothes in the wash basket.
If you own 72 plectrums, it becomes quite easy to find one.
Cheers
Dave