An opportunity cost calculator.
Economists often discuss things (wages, gdp, interest rates) in real terms. This is where the thing being discussed is adjusted to inflation, but people usually don't think in terms of opportunity costs. Now you can!
What is opportunity cost? The textbook definition from Google is: "the loss of potential gain from other alternatives when one alternative is chosen".
Every dollar you spend today is a dollar less you have to spend tomorrow. In the context of investments every dollar you spend is a dollar you cannot spent or invest tomorrow.
This site will show you what a purchase historically* would have been worth if invested over certain time frames in different assets. The point of this is not to recommend one or any investment, just to illustrate the possible opportunity costs of spending today.
Additionally if you work for a living every dollar you spend has a different type of real cost: your time.
Assuming all your financial wealth comes from working it is possible to calculate exactly how much time it takes for you to earn enough to buy something. The results may surprise you!