“Fees for a merchant accepting bitcoin payments often range from nothing to less than 2 percent because of the open nature of the technology. Coinbase, for example, said it did not charge its merchants for the first $1 million in sales, imposing a 1 percent fee after that on the conversion of bitcoin into local currency. Circle said it had not settled on pricing for merchants, but that it would charge them a fee to use its system that would be well below credit card transaction costs. Mr. Allaire and others predict that merchants will encourage customers to spend bitcoin by passing some of the savings on to them in the form of lower prices or other rewards.”
http://www.nytimes.com/2013/10/31/technology/bitcoin-pursues-the-mainstream.html?pagewanted=all