When an options trader wants to buy or sell an option he / she can get the latest price from an electronic database, which is usually provided by the brokerage firm.

If a trader wants to place an order to buy options, she usually pays the ask price. If the trader wants to place an order to sell options, then she will usually receive the current bid price. The spread between the bid and ask prices are usually at a higher percentage of the price of options compared to bid and ask spread percentages of stock prices.