Charging the customer a fee for taking the payment via cc is a grey area, Based on information I have read it can be understood in different ways. Below are just some items I have found on the subject.
You might want to check with your acquirer - apparently charging customers a surcharge for using a credit card is against VISA/Mastercard scheme rules, and should also be detailed as disallowed in your merchant acquirer contracts, and could result in your merchant account being terminated.
"EDIT: Here's the relevant part of the Mastercard scheme rules:
A Merchant must not directly or indirectly require any Cardholder to pay a
surcharge or any part of any Merchant discount or any contemporaneous
finance charge in connection with a Transaction. A Merchant may provide a
discount to its customers for cash payments. A Merchant is permitted to
charge a fee (such as a bona fide commission, postage, expedited service or
convenience fees, and the like) if the fee is imposed on all like transactions
regardless of the form of payment used, or as the Corporation has expressly
permitted in writing. For purposes of this Rule:
1. A surcharge is any fee charged in connection with a Transaction that is not
charged if another payment method is used.
2. The Merchant discount fee is any fee a Merchant pays to an Acquirer so
that the Acquirer will acquire the Transactions of the Merchant.
EDIT2: Here's the Visa section:
5.1.C Prohibitions
A Merchant must not:
• Add any surcharges to Transactions, unless local law expressly requires that a Merchant be permitted to impose a surcharge.
However, according to
http://www.opsi.gov.uk/si/si1990/Uksi_19902159_en_1.htm (for UK transactions) it is allowed to surcharge for credit card transactions, but only to the amount actually charged for the service. So, you could not impose a 2% surcharge if you actual transaction charge was only 1.8%, for instance".
You really need to be careful about what you do before you rush headlong into trying to implement a surcharge to ensure that you're acting within the law. I would not risk passing the charges on. Well, at least that's my take on it, but bear in mind I'm a carpet cleaner not a lawyer.