The value of something is equal to what someone else is willing to pay.
This painting by Picasso was sold at auction a few days ago for about 40 million dollars. This is the same as the combined life earnings of about 100 people (before tax) in the Western world. In a poor country it is probably more than 1,000 people (or families).
- Sotheby’s sells Picasso portrait for $40 million (money.cnn.com)