On the basis of household‐level scanner data (called homescan data) for Japan, we construct a household‐level price index and investigate the causes of price differences across households. We observe large price differentials across households, a result that is consistent with the previous research based on the data in the USA. However, the differences across age and income groups are small. In addition, we find that elderly people face higher prices than the younger ones, which is contrary to the results of the previous research. The most important determinant of the price level is the extent to which households rely on bargain sales; doubling purchases of goods at bargain sales decreases the price level by about 2%, while shopping frequency only has a limited effect on the price level.