This is the price of demand, so the price at which you can sell a desired currency to a broker. If you look at any currency pair on the price chart in the terminal (or other tool) and open a "New Order", you will see that you are offered two prices: one price is Ask (see), and the other is Bid. It's like in a normal currency exchange, when you have returned from a trip abroad and you need to sell the rest of the foreign currency you have left. For you, the bank sets the sales price, Bid - it is always slightly lower than the price of Ask. So, if you want to make a deal for sale «Sell» (see) of a currency pair in the terminal, then it will open your transaction at the Bid price, just slightly lower than the price that you see on the chart. At first, you will be in a small negative, do not worry, this is called "spread" (see), it's a commission, which the broker takes for each transaction.