So you'd have to pay interchange, plus whatever your processor charges on top of that, which will depend on them, and volume. You can definitely shop around a little bit, there's probably several local people who can talk you through it and bring you some offers to the table from various processors, but also get a quote from people like TSYS, First Data, and Chase Paymentech directly.

I'm remembering fees varying from $.05 to $0.10 and 0.10% to 0.15% on top of interchange. The visa interchange rates are available at (1) to give you an idea. You're mostly interested in the eCommerce categories probably, so you'll be paying 1.80 to 1.95% plus $0.10 on top of whatever you're paying from you're processor for credit cards, debit cards are cheaper.

Many people that do micropayments will try to combine some transactions together, in order to save money. That said, you might be interested in paypal micropayments (2), as they only charge $0.05 + 5%, which for a $2 transaction, is a big savings.

1: http://usa.visa.com/download/merchants/visa-usa-interchange-...

2: https://www.paypalobjects.com/IntegrationCenter/ic_micropaym...