Official errata sheet shown it that "Heros can no longer immediately turn in a treasure card from a chest to receive its full value.Instead,they must carry the item back to town and sell it for half value in the town shop"

My treasure cads in game box haven't the cost printed.So I think it will be printed in expansion rules,but I haven't any expansion

Which linked page can I found for the cost of treasure card

The costs of treasure cards are listed on page 18 of the base game rulebook, under "shopping". The same table also appears on the back cover of the quest guide.

aha~~~GOD! I'm stupid