There are sometimes exceptions to the law of demand:
1. Articles of distinction: it is also called Veblen effect. According to Prof. Veblen, there are some goods which are articles of distinction. These articles are demanded buy the consumer due to high price. If their price falls people will not buy it.
2. Giffen goods: this concept was given by Sir Robert Giffin and it is also called Giffin Paradox. These are inferior goods. According to it if the income of the consumer increases then the demand of such commodities will fall on the other hand if the income of the consumer falls then demand of these products will increase.
3. Ignorance: sometime people buy costly goods due to the ignorance. They don’t have the knowledge regarding the value of the product.