Price semantics
An ask is a sell-listing quote; a bid is a buy-order quote.
Amount, side and quantity
An ask is a sell-listing quote; a bid is a buy-order quote. Ordinary quotes use the market's currency and do not include the separately computed CNY fee tiers. Amounts are decimal strings to preserve precision.
quantity=null means unknown; quantity=0 means no available quantity in that row. is_quantity_minimum=true marks a lower bound. is_all_items_same_price=false means the quote does not describe the price of every unit; null means unknown.
Missing and delisted prices
A source can report no amount, yielding market_price_amount=null. Delisting retains the last known amount but sets quantity=0 and delisted_at. Do not turn either state into a zero-priced opportunity.
An item may also have a CSCP estimate with side=mid and no quantity. Apply your own freshness and availability checks before acting on data.