The only costs to accept online payments are a per transaction fee. The fee for credit/debit cards if you qualify for the non-profit rate (501c3 status required) is 2.3% + $0.30 per transaction for all cards except American Express. The American Express rate is 3.5% + $0.30. The standard credit/debit card rate is 3.0% + $0.30 per transaction. The fee for ACH is 0.9% (maximum $6.50) per transaction.