Wiki price accuracy

[Ephirith]

Depends on the item. There are also a few sellers you want to avoid... they sit in the tunnel and scoop up items at the low end of their price range, then resale them at high prices. Spend enough time in the tunnel and you'll learn who they are.

For some reason some items haven't appreciated much, while others have tripled in price. Your best bet is to just be patient until you find the item you want for an acceptable price, or farm it yourself.