No. You will not be charged for placing, updating, or canceling a bid. You are only charged if your bid wins - and then, only at the final ticket price (which will always be less than or equal to your bid amount, less any taxes and fees).
After placing a bid, some bidders may notice on their credit card statement a hold for the total amount of their bid. Please note that if this happens, it is not a charge, but only a temporary placeholder (i.e., it will not be applied to your balance) that will last for approximately seven (7) days. The reason for the placeholder is so that we can verify your payment method and available funds at the time your bid is placed. This helps to ensure that your payment method is ready to be charged at the end of the event campaign should you hold a winning bid.