How close to he bid or ask price do you get when you buy or sell an option? If the bid and ask quote is 0.50 and 0.52, and you try to buy a contract, and assuming nothing changes between the time you read the quote and the order is placed, are you going to get the contract for 0.52? Or is there a better chance that you're going to be paying more than 0.52? Also, is there a good formula or rule to judge the spread? Whether it be formal or informal?