How to read a price history chart on VantaSpec

Every product page on VantaSpec has a price history chart. It answers the question a single price cannot: is this actually a good price? Here is how to read it.

What is recorded

We record a price every time it changes, at every retailer we track. Nothing is recorded while a price stays the same, so the chart is drawn as steps: each line stays flat until the next change, then jumps. A long flat line means a stable price, not missing data. The chart runs to today, so the right-hand end of each line is the price now.

New and refurbished stock are kept apart. A refurbished or open-box price never appears on the chart for a new product, so it cannot make a new part look cheaper than it is.

One line per retailer

Each retailer has its own line and its own colour, and the colours stay the same on every product so you learn them. Use the legend to switch retailers off and on; hover (or tap) on the chart to see every retailer's price at that moment.

Prefer numbers to lines? The table view under the chart lists the same data.

The "lowest" line

The lowest line is the cheapest new price available anywhere at each moment. When one retailer raises its price and another is cheaper, the lowest line moves to the other retailer, so it shows what you could actually have paid, not one retailer's history.

Why some low points are not counted

Retailers occasionally show a wrong price for a few minutes: a typo, a pricing glitch, a deal that sells out at once. Our headline figures, such as the lowest price recorded, only count a price that held for at least six hours. A brief spike still appears on the chart, but it is never quoted to you as a deal.

Reading it like a buyer

• A price at or near the lowest line's floor is a good time to buy.
• A "sale" price that matches last month's normal price is not a deal. Look for a recent jump up before the "discount".
• A slow fall over weeks often means a newer model is coming. If you can wait, waiting may pay.
• Lines that stop usually mean a retailer stopped selling it.

Where the numbers come from

Prices come from retailers' product feeds and from reading retailers' own product pages, and every price links to the page it came from. How we source prices explains the checks behind them.