Burgers aren't just for eating. They can also tell you a lot about the economy. The Economist's "Big Mac index" compares the price of the McDonald's hamburger around the world to determine whether a currency is overvalued. So which country has the cheapest Big Mac? India takes the crown. You can pick up chicken- or mutton-based Maharaja Macs for just $1.54. South Africa is next at $2.16, followed by Malaysia at $2.23. Burger lovers will need deeper pockets in Norway, where a Big Mac costs a whopping $7.80. For nearly 30 years The Economist has used the index as a lighthearted way to determine whether currencies ... (full story)