Interesting to see Jon Freeman's note above. I got my first good anglo concerina that way in the 70's. A G/D Jeffries that was already spoken for; I knew after 10 seconds it was for me. Rather than try to convince the purchaser that the didn't really want it, I too asked for the right of first refusal, and got a postcard about 3 years later. I had to lose a really nice Edeophone in trade but it was worth it.