Actually since the auction claims you get a binder full and shows many pages of them, you cannot change the rules of your listing because you made a mistake. That is a violation of listia rules. You will be obligated to send all the cards as mentioned in the listing and you will have to provide free shipping as stated. All of these people who are ok with you changing the description of your auction must be new as well. If you did not do your research prior to listing then it is on you. I would be very cautious next time.