Original sentence: In economics, a luxury good (or upmarket good) is a good for which demand increases more than proportionally as income rises, so that expenditures on the good become a greater proportion of overall spending
Edited sentence: In economics, a luxury good (or upmarket good) is a good for which demand increases more than proportionally as income rises, so that expenditures on the good become a greater proportion of overall spending, for example a black handbag from Wal-Mart priced at $15 is not in high demand because virtually everyone can afford it, people are programmed to want what they can't have (or afford) or have luxury items possessed by the wealthy or celebrities, a $10,000 Gucci handbag is in such high demand that the company can price it accordingly, catering to a select few