Explain the practice of tying and discuss why it is controversial.

Tying is the practice of bundling goods for sale. It is controversial because it is perceived as a tool for expanding the market power of firms by forcing consumers to purchase additional products. However, economists are skeptical that a buyer's willingness to pay increases just because two products are bundled together. In other words, simply bundling two products together doesn't necessarily add any value. It is more accurately believed to be a form of price discrimination.