How we measure
Sources
| Section | Source | What we read | How often |
|---|---|---|---|
| Games | Steam store API (US region) | List price, current price, discount | Daily |
| Games | CheapShark | The same game at Green Man Gaming, Fanatical, Humble, GOG, Epic and other stores, in USD | Daily |
| Tech | Best Buy Products API | Current price and regular price by SKU | Every 6 hours |
| Travel | Open exchange-rate feed (USD base) | Mid-market rate per USD for 17 currencies | Daily, when the feed updates |
All sources are public pages or official APIs read on a fixed schedule with an identifying user agent. We do not scrape sites that forbid it, and we do not buy price data.
What counts as an observation
One observation is one value for one item on one day. If we read the same value several times in a day it is still one observation; if the value changes within a day, that is a new one. The count you see next to every figure — "measured 9×" — is the number of distinct observations behind it.
What we publish from the data
- Tracker pages (
/track/…): one page per item, rebuilt daily — current price, 90-day low and high with dates, 30-day median, a chart, and the same item at other stores. A tracker page is only listed for search once an item has at least seven observations and its price has actually moved; before that it exists but is marked not to be indexed. - Posts: written only when an item departs clearly from its own 30-day median. Every number in a post must exist in our log or a cited source, and every post is reviewed by a person before it goes live.
- Raw data: each tracker and each post has a JSON file with the observations behind it. Cite the observation time when you quote us.
What we do not do
- We do not write from memory or copy other sites' prices.
- We do not invent history: if we started tracking an item last week, the page says so.
- We do not hide that software helps produce drafts. Review and approval are done by a person, and the approval log is kept.
- We do not adjust prices for taxes, shipping or regional pricing. Store prices are as shown to a US visitor at observation time.
Limitations
Stores change prices between our observations; a price may have moved since the time shown. Key-store prices depend on region and payment method. Exchange rates are mid-market and differ from what a card or exchange desk gives you.
Questions about a specific number: see Contact.