just as "location location location" is an absolute in business,
"What the market will bear" is the absolute for any used merchandise
for accordions, this is complicated by the fact that accordion value is
primarily (to the general market) based on perception, which is typically
based on fairy tales
if you look on Craigslist or eBay for used accordion pricing,
it is easy to think a 2 reed accordion is worth $900 unless you realise
the 2 reed accordions listed have been for sale for 3 or 4 years
at those prices, the ads renewed perpetually
on places like this forum you have a chance to hear from real people
and get more realistic prices
a reputable dealer like Mr. Smythe price used instruments largely
on 1: what they had to invest into them (trade in, auction item, etc.)
2: how much work they had to invest in them
and 3: their standard markup formula based on their experience and business model
it is likely a fair price on this basis, for this specific accordion, at this time
a 5 reed accodion like this is a special beast, and not something just
anyone could hope to tame and use effectively, but you can get an amazing
sound out of them, and it would likely serve you for the rest of your life
good luck on your quest