You can’t just use common items though
That is kind of the point, because once you add more than common sense items, mostly sold in standardized sizes, the list is both endless and individual. So the best bet is to use an add-on “guesstimate” on top of the calculated amount.
Many years ago I did comparison shopping at different grocery stores, of a long list of items I normally purchased, and was able to reach generalizations of each store.
One was most expensive across the board.
One was least expensive across the board.
One was best for bulk purchases of mostly staples.
One was best for purchases of produce.
One had best selection and lowest prices for meats.
Thus, with just a bit of prior planning, by shopping at different stores, despite using some time and gasoline, you could save thousands of dollars every year.
Which brings us back to trying to calculate the inflation rate. Oddly enough, it does not have to be too accurate, as for once it is not about you *saving* money; but being fair to someone you are paying for labor.