The bid price (or simply “bid”) is the amount a trader is ready to pay for an asset. In an order book, the highest bid price is always lower than the lowest ask price, and the difference between them is called the spread.
In an order book, the order with the highest bid price is the first to be filled when a trader places a market sell order.
You can check the current bid price under the price chart on the Trade page of the CEX.IO website. It’s displayed in the Buy orders box.