There are no charges for adding a debit/credit card to your Rely account.
However, when you link a debit/credit card to your Rely account, we send a request to the bank to verify that the card is valid and bank will allow it to be used. This authorisation check will temporarily hold a small amount during this process. Rely reverses the authorization request immediately, but it may take 7-10 business days for the pending authorization to disappear from their bank statement. (Don’t worry you are not charged for link your debit/credit card, its just the delay)