Question 1

How does the Price Tag Time Machine calculate my accuracy score?

Accepted Answer

Your accuracy is the percentage difference between your guess and the verified historical price. We take the absolute difference, divide it by the actual price, and subtract from 100 — so a perfect guess scores 100% and being off by half the price scores 50%.

Question 2

Where do the historical product prices come from?

Accepted Answer

Prices are researched launch-era retail figures drawn from manufacturer records, contemporary advertisements, and historical references. Each item links to its primary source so you can verify the figure.

Question 3

How is the inflation-adjusted today's dollars value calculated?

Accepted Answer

We use the U.S. Bureau of Labor Statistics Consumer Price Index for All Urban Consumers (CPI-U). The historical price is multiplied by the ratio of today's CPI to the item's year CPI.

Question 4

What is the difference between Unlimited Arcade and Daily Time Machine?

Accepted Answer

Unlimited Arcade serves random items from your selected decade for endless play. Daily Time Machine gives every player the same single iconic product each calendar day.

Question 5

Is Price Tag Time Machine free to play?

Accepted Answer

Yes. The game is completely free, browser-based, and requires no sign-up. It is supported by display advertising.

Price Tag Time Machine — Guess What Things Cost Back in the Day