Why the buying and selling rates are never the same
What the spread between buying and selling actually is, where it comes from, and how to tell a good rate from a bad one.
Every exchange quotes two rates: the one it buys your currency at, and the one it sells to you at. The gap between them is the spread.
Where the spread comes from
It covers the cost of holding cash in many currencies, the risk of the rate moving during the day, transporting and insuring banknotes, and simply running the branch.
To compare shops, look at the spread rather than one side of the quote. A narrower spread is the better deal.