Reading this OP, it seems the topic addresses for-sale ads posted by Audiogon users and not the retail pricing shown in Audiogon's own Bluebook service. FWIW, I occasionally find misleading retail pricing on other sites too, such as USAM.
I agree with all the responses and routinely check HiFi Shark, professional reviews, retailer websites, and the manufacturer's own websites. You definitely need to do your homework.
For fun, I just looked up my speakers on Audiogon's Bluebook, where you can see the posted retail price without joining or paying a fee. However, you need to pay if you want to access Audiogon's selling price history. The posted retail price of my speakers was about $2,900 lower than the current retail price, due to refinements and price increases over the 22-year life of the still-current model. For products with longevity, the appropriate posted retail price could vary based on the specific iteration of the item for sale.