I just purchased $0.55 worth of food on a credit card. Yeah, lame. I should have used cash. But, I like the convenience of not getting back $0.45 in change and it isn't like I'm going into debt for this expense. Having dealt with credit-card transactions fees, paypal fees and other merchant-account fees, I know that a business has to deal with these fees somehow.
So, the question is, if I knew how much the hidden transaction fees were, would that change my actions as a consumer?
I think it would. Take for instance the example mentioned above. If on a normal transaction a company is charged $0.20 for just processing the transaction, and another 2-3 percent for the transaction amount, then my small purchase really hurt; on-the-order of almost half the value of the transaction. This either means that they break even with other purchases that have a better ratio of revenue to the fees charged, or they have to charge each transaction more to process the smaller amounts.
So, since I know about transaction fees, wouldn't it be in my self-interest to use cash to keep the prices lower?