The fees associated with a merchant account will remain unchanged from whatever is reflected on your GiveSmart Fundraise agreement; there are no additional fees or setup costs associated with the merchant service.
The usual fee is $10/month from CardConnect, but check your agreement for the specifics.
Whereas with the legacy remittance option, all fees are taken out before the check is sent, with a merchant account active, the full amount of collected donations will be deposited to the linked bank account, with fees being withdrawn at the end of the month.
For more answers about merchant services, review the Frequently Asked Questions.