A way for me to understand currency exchange rates

Yes, a rather pedestrian topic but I thought of it as I took a walk yesterday, so that makes sense.

Economics as a field is not an area of strength. In fact, I'm not clear on many things that are listed as "fields". I never understood the field of aerodynamics, I never understood the politics behind behind being a left or right fielder, and Sally and Kim have always been Fields I couldn't figure out. But enough about them.

The idea that different places use different currency seems wrong to me -- that's as reasonable as having different places use different words for the same thing. (cf https://www.youtube.com/watch?v=DOJDNChwgBw ). Then you have this phantom notion of an exchange rate which, as best as I can understand it means that if I give you 10 dollars today and I get 47 Foreign Monopoly monies today, I might get 46 or 48 in exchange tomorrow based on the presence of other factors, like nuclear war. That seems rather complicated (the exchange; the war seems rather straightforward).

I need a standard (something that I can really relate to, so not a gold bar which, as far as I know, only exists in movies and iPhones) that can help me understand a more important currency trait, "buying power." So let's take a random household item -- Head And Shoulders Classic Clean Dandruff Shampoo, 12.5 ounces. I can get that at a store for 6 dollars, but I know there are differences around the country so we should take a national average and say that 1 bottle equals 6 dollars.

Now when I get ready to travel and I look up different currencies, I don't really understand this notion of "I give you 1 American dollar and you give me 3.4 million of your plastic beads" until I know what I can get with said beads. The exchange board could look more like this

6 USD=21.93 NIS which equals 75% of a bottle of H+S (I found it online for 27.90 NIS)

So now I know not how many shekels a dollar is worth, but what the buying power of my dollar.

As an extension, you can set the system up to automatically retrieve the average price in a particular country for a variety of products, or you can make a sample order from, say, Amazon, and have the system tell you how many American dollars-equivalent in local currency you would need.

Later, when someone says "it's a good time to travel because the dollar is getting a great exchange rate" I can have that person explain "six USD will get you 13 bottles of H+S in Greece because it is worth X drachmas and H+S costs Y."

The defense rusts.