Different people have different buying power. Fact. Some things which may be cheaper for someone may be costly for another one. Fact. A large proportion of the population comes below the poverty line and even a meager amount of "$10" is a large sum for them. It can amount to their meal for a week whereas an affluent business man may tip $ 10 to a waiter in a restaurant.

The Principal reason for this price discrimination is the "Economy". Now the economy is a broad term and covers Life expectancy, Standard of living, Gross domestic product, National Income and Money regulation. Some places have such a smooth and transparent money regulation and deregulation that their currency experiences a boost and becomes one of the most powerful in the world whereas in some places the money circulation can be affected by some malpractices such as hoarding, nepotism, corruption and illegal trafficking; these can be so prominent and widespread that money loses its value and becomes one of the lowest valued currency in the world. This is the basic and most essential reason for the money disparity being prevalent in the society.

Have a look at the Asia and consider the value of currency in various countries such as India, Pakistan, Korea, China and you will notice that the currency value is almost 50th or 40thpart of the dollar or pound. Even "Dollar" word is a lavish word for the people over here and they have a perception of it as if it belongs to heaven and cosmic bodies. United States and Australian dollar figures such as 5 dollars, 10 dollars, 50 dollars are big words for the people and a plenty of things can be bought in $10 in Asiatic countries.
You can purchase a 5 day 3 times meal, 2 days stay in a 3 star hotel, and one full day enjoyment in an amusement park in the countries like Pakistan and Nepal with this amount. Moving to the middle-east side of the world there are the Gulf countries, who are tax free and a lucrative sector to invest. Their major highlight comes in the form of oil reserves they own and currencies such as dinar are up to 150 times the Indian rupee and 3 times the American or Canadian dollar. For these countries an amount of 1 dinar is a normal thing, but outside their borders these people are really rich and wealthy persons.

Other currencies such as Dirham and Rial are around one third and one fourth of the dollar or Pound. Though $ 10 dollars is not a big amount in these countries, but still you can buy bag full of groceries and maintain your 3-4 days supply of electricity and water charges. Zimbabwean dollar is around 600th part of a $US. You can rent a hotel for months and buy food almost for a year with 10 USD.