Mass discount retailers entered the market since 1960s. A typical example is Wal-Mart. They originally (and most of them still) targeted at lower-income customers and offered broader lines of products than department stores like the Macys and Sears. In 1960, the combined sales of discounters were $2 billion and that of Wal-Mart alone increased to $218 billion for the fiscal year ended January 31, 2001. While mass discounters continued to prospered, another type of discounters were introduced in the early 1980s wholesale clubs. Take Costco as an example, the company became the largest wholesale club in the industry with sales of $34 billion in 2001. Although it is smaller than Wal-Mart, Costco adopt a different set of business strategy and delivered its value in a different way.

Compare Wal-Mart vs. Costco Wholesale Corporation and list the business strategies (different from Wal-Marts) that Costco employs to deliver value to its customers. Note: news articles and companys annual reports could be good source of evidence. Please cite each news article or companys annual reports.