As a result from an anti-trust settlement from a lawsuit filed back in 2005, retailers now have the ability to charge customers up to 4% of their purchase cost for using a credit card, as of January 27. The "checkout fee" applies to only credit cards -- not debit cards -- and can only be implemented in 40 states in the US, with California, New York, and Texas being some of the states where the surcharge is illegal.
Before you get too bent out of shape, be aware that it's the retailers who have the power whether or not to implement a surcharge, and if they do, they have to choice of deciding what percentage, but only up to 4%. While it's not yet known how many retailers plan on implementing a credit card fee at checkout, we can't imagine the backlash of such a decision being subtle.
The new fee comes from an anti-trust lawsuit filed by retailers who were being tricked by credit card companies that were all discovered to be fixing the fees that retailers pay to process credit cards. Essentially, every retailer pays a fee to a credit card company for the ability to accept that particular credit card in its stores. This fee would basically just be passed on to customers.
It's a questionable practice, but it seems that it's been given the go-ahead. Retailers will be forced to notify its customers if they do end up implementing a credit card surcharge, so there's no risk of being surprised when you get to the checkout counter. Other than that, though, it looks like cash and debit cards may become more popular as a result. Only time will tell.