With the holiday season upon us, one personal finance site is sounding the alarm on a ubiquitous retail payment plan that many Americans say should be outlawed. It’s called “deferred interest." In a typical scenario, the shopper puts a big purchase on a store credit card. The retailer promises to charge no interest if the buyer pays off the balance within a set time frame. The problems start if you fail to repay the entire sum before the promotional clock runs out. At that point, the deal is off and the ...