Account linking fees are calculated based on the number of successful requests made to the /link_account API so if you link an account, unlink it, and link another one, you get charged an additional $1 for the 2nd account. However if you link an account, unlink it, and try to link another one but it fails, then we don't charge for the 2nd account.
One linked bank account is included at no additional cost as part of the KYC/KYB identity verification.