FYI here is the MO Department of Revenue policy when you pay taxes.
Debit & Credit Card
The Department accepts MasterCard, Discover, Visa, and American Express. Debit cards are accepted and processed as credit cards. Please allow 5-6 business days for debit and credit card transactions to apply to your tax account. Please note that your payment will be postmarked the date you submit payment. There will be a convenience fee of 2.0% + $0.25 per card transaction, regardless of amount
NOTE: The handling or convenience fees included in these transactions are being paid to the third party vendor, NCR Corporation, not the Department of Revenue. This includes NCR Corporation' right to electronically debit a service charge in the amount of $25.00, if applicable, for the processing of an Insufficient Funds or Closed Account transaction from your designated bank account in addition to whatever charges your bank may assess. By accessing this filing and payment system, the user will be leaving Missouri's website and connected to the website of NCR Corporation. The website of NCR Corporation is a secure and confidential website.
EDIT just checked several other states and they ALL have a surcharge if paying by CC or Debit Card in excess of 2%. Guess Government does not want to give free money to the banks.