The Economist tried to solve this in the past with https://www.economist.com/interactive/big-mac-index (https://en.wikipedia.org/wiki/Big_Mac_Index for non-subscribers)
I often toyed with the thought of a TP index... literally the spend on something you use to wipe crap off your rear and throw away.
I often toyed with the thought of a TP index... literally the spend on something you use to wipe crap off your rear and throw away.