Ever wonder how much that $20 bill would have purchased in 1950? Or how much that same $20 would be worth today had you invested it in the stock market back in 1970? There are a couple of great online tools and apps that help you do just that. The American Institute for Economic Research has a great cost of living calculator that lets you put in a dollar amount and compare that amount between two years:
Foodtimeline.org is a great source for tracking food prices throughout American history. They've got great lists like "The Hershey Bar Index" and historical prices of McDonald's Hamburgers. In 1955 a Hershey bar was just 5¢ and a McDonald's hamburger was 15¢.
But what if instead of spending your 20¢ on candy and burgers, you had invested it in 1955? Well, there's an app for that, of course. MeasuringWorth.com has an app called The Time Traveler's Investment Calculator. "The Time Traveler’s Investment Calculator is a simple way to go back in time and choose a hypothetical investment strategy and see how you would have done. You can compare your actual investments with what you wish you had done."
But if apps aren't your thing and you want to kick it old school, check out The Value of A Dollar: Prices and Incomes in the United States. This is a great resource for historical products and services dating back to 1860 and is almost always found in your local public library's reference section.