But there is not much agreement about by how much. There are many problems and much subjectivity in trying measure price indices.
Different people buy different things.
The products for sale at different times are different. Most would agree that it is. Consider the range of prices for a bottle of Budweiser beer for example. There is probably at least a factor of 5 difference between the price in a fancy restaurant or international airport, or a convenience store, or on sale in a big liquor store. Others have pointed out that the same item may cost less at a discount store, but it may be farther away and cost time and gas to get it there.