Every price on this site is a reading taken at a moment in the past, by a client that watches the market one item at a time. Nothing here is a live feed.
The prices should be close to what you see in game.
Still useful. Check in game before committing a large amount.
Treat every figure as a lead, not a fact. Verify before acting.
No reading at all — deliberately blank rather than shown as zero.
Why the last one exists
Some items cannot be searched cleanly — asking for book returns enchanted books, because the server matches enchantment text. When that happens there is no reading, and the site says so instead of printing a zero that would read as “nobody wants books”.
The habit worth having
Before a large order, open /orders for that item yourself. It takes five seconds and it is the difference between trading on data and trading on a memory of it.