Department stores today have sections that sell the following: clothing, furniture, home appliances, toys, cosmetics, gardening, toiletries, sporting goods, do it yourself, paint, and hardware and additionally select other lines of products such as food, books, jewelry, electronics, stationery, photographic equipment, baby products, and products for pets. Customers check out near the front of the store or, alternatively, at sales counters within each department. Some are part of a retail chain of many stores, while others may be independent retailers. In the 1970s, they came under heavy pressure from discounters. Since 2010, they have come under even heavier pressure from online stores such as Amazon. 

The origins of the department store lay in the growth of the conspicuous consumer society at the turn of the 19th century. As the Industrial Revolution accelerated economy expansion, the affluent middle-class grew in size and wealth. This urbanized social group, sharing a culture of consumption and changing fashion, was the catalyst for the retail revolution. As rising prosperity and social mobility increased the number of people, especially women (who found they could shop unaccompanied at department stores without damaging their reputation), with disposable income in the late Georgian period, window shopping was transformed into a leisure activity and entrepreneurs, like the potter Josiah Wedgwood, pioneered the use of marketing techniques to influence the prevailing tastes and preferences of society.
When did they start?
at the turn of the 19th century