For some goods, the main cost of buying the product is not the price but rather the time it takes to
use them. Only about 0.2% of consumer spending in the U.S., for example, went for Internet access
in 2004 yet time use data indicates that people spend around 10% of their entire leisure time going
online. For such goods, estimating price elasticities with expenditure data can be difficult, and,
therefore, estimated welfare gains highly uncertain