I bought a coffee grinder for full price on a Monday. On Friday it went on sale for thirty percent off. The grinder was fine, but the timing bugged me for a week. That is when I found out there is a free tool that shows you the price history of almost anything, and I have not overpaid since.

Use a Price History Tracker

Websites like camelcamelcamel and Keepa track price history for items sold on Amazon. Paste the product link into the site and you get a graph of the price over months or years. You can see exactly what the item has sold for, and whether the current price is a deal or a trap.

Check the Price Range Before You Buy

Before any non-urgent purchase, look at the low and high points on the graph. If the current price is near the top of the range, the item will probably drop again. If it is near the bottom, buy now. I now treat that graph like a stock chart, because it basically is.

Set a Price Drop Alert

Most trackers let you set a target price and get an email when it hits. Add the item to your wishlist, set the alert, and wait. The tool does the watching so you do not have to refresh the page every day.

Watch for the Fake Discount

Here is the part that sold me: some sellers raise the price for a week, then “discount” it back to normal to look like a sale. The price graph exposes this instantly. I caught a pair of headphones doing exactly that, and the so-called deal was ten dollars more than the regular price from last month.

Know When the Big Drops Happen

Prices on many items dip around Prime Day, Black Friday, and right after big holidays. If the graph shows a pattern of annual drops, set your alert for the known low and wait for the cycle.

I check the graph for anything over twenty dollars now. It takes one minute and it has saved me a lot more than the grinder cost.