Travelers can purchase U.S. dollars from the United Kingdom's Post Office by ordering online up to five workdays in advance, picking them up at one of more than 10,000 Post Office locations or having them delivered to a home. Orders placed before 3 p.m. are delivered the next workday. Any unused dollars are repurchased by the Post Office commission-free with a receipt.
For online orders as of July 2014, the exchange rate between British pounds and U.S. dollars is 1 pound for approximately $1.66. Online orders for dollars range from 400 pounds to 2,500 pounds. An order placed on Friday is delivered Saturday with an extra fee of 1.50 pounds. The more currency ordered, the cheaper the rates for dollars become.
Dollars are picked up "on demand" at physical Post Office locations. Other currencies available at United Kingdom Post Office locations include the euro, the Canadian dollar, the Turkish lira and the Croatian kuna. Traveler's checks are also available.
A rough estimate for souvenir spending includes taking 60 percent of the dollar value to calculate the cost in pounds. For instance, a $30 souvenir is roughly 18 pounds. The Post Office recommends checking the exchange rate before taking a vacation to ensure the best value for an overseas trip.