With regards to differentiating prices of products by category over time, this chart looks relevant: http://www.roseassociates.ca/20-years-of-price-changes-in-t

With regards to differentiating prices of products by category over time, this chart looks relevant: http://www.roseassociates.ca/20-years-of-price-changes-in-the-united-states-selected-consumer-goods-services-wages-january-1998-to-december-2018/ http://www.roseassociates.ca/20-years-of-price-changes-in-th... "The Price of Tomorrow" by Jeff Booth really nails this concept.