If a visitor to Venezuela is unfortunate enough to pay for anything with a foreign credit card, the eye-watering cost might suggest they were in a city pricier than Tokyo or Zurich. A hamburger sold for 1,700 Venezuelan bolivares is $170, or a 69,000-bolivar hotel room is $6,900 a night, based on the official rate of 10 bolivares for $1. But of course no merchant is pricing at the official rate imposed...