An asking price is not a sale
A listing shows what someone wants. A completed sale shows what was paid for a particular copy. Sales are only comparable when condition, language, printing and extra costs match. One unusually high sale does not establish a dependable price for every other copy.
Time and sample size matter
A median of many relevant sales means something different from one old transaction. Check the observation window and count where available. No recorded sales may mean missing coverage rather than no demand.
Currency conversion is only part of the story
Converting dollars to euros does not remove differences between markets. Shipping, import costs, language and local demand still matter. A directly observed EUR valuation should be distinguishable from a converted or modelled estimate.
Before buying
Check several comparable listings or sales. Verify number, language, condition, date and shipping. When prices differ sharply, look first for a different variant or a stale source. Use our deal check with a reference you can explain.