Where the prices come from
Our primary source is the Impact Catalog API, which carries the same official product feeds stores publish to their affiliate partners. That currently covers Walmart, Best Buy, Kohl's, SharkNinja, Roborock, Anker and Home Depot; Amazon is shown as a "check price" button only. Every tracked product is checked at least once a day, and each check is stored as a timestamped price point that is never edited afterwards.
A measurement has to prove itself before it counts: the currency must be USD, the price must be plausible against the product's other stores, and the listing must be verifiably the right product (model code or exact GTIN/UPC match). Obvious glitches, such as a $3 "robot vacuum" or a price 5× the others, are rejected or quarantined automatically, and quarantined points are kept, not deleted, so the record stays auditable.
We also record who is selling: listings from third-party marketplace sellers and bundle listings are tracked separately from first-party store prices, and marketplace rows are labeled as such. A marketplace or bundle price never silently becomes "the price" of a product.
How a verdict is computed
Today's best new-condition price is judged against the product's own 90-day record: its average, its real low, and how long past "sales" actually lasted. The thresholds:
- Real deal: at least 10% below the 90-day average and at or near the 90-day low. A genuine drop worth acting on.
- Typical price: within roughly ±5% of the 90-day average. Nothing special is happening, whatever the banner says.
- Inflated: the advertised discount is measured against a strike-through price that wasn't the real price in our records (more than 15% above the 90-day average), or the price was raised in the 14 days before the "sale" began. These are listed on Fake Sale Watch and never appear in Price Drops.
Two things we never do: we never publish a "was" price we didn't record ourselves, and we never compute a verdict from less than 30 days of history. Young products are labeled "building history" instead. Verdicts are a judgment about the legitimacy of a price, not an opinion about product quality.
Verdicts are recomputed every time new price data lands, and each one stores the numbers it was based on, and the verdict you see links to the history that produced it.
Why refurbished is kept separate
Refurbished and open-box listings are real savings but a different product promise, with a different warranty and a different return path. They're shown on product pages as clearly separated rows and are never counted in new-price history, so a flood of refurb stock can't fake a "price drop" on the chart.
Affiliate disclosure
Some store links on Cheaplorer are affiliate links: if you buy through them, the store pays us a commission. It does not change the price you pay. More importantly: commissions never influence prices, rankings or verdicts. The tracker doesn't know which store pays what. It sorts by price, and the verdict math is published on this page. If a store with no affiliate program has the best price, that store is shown first.
Corrections
Price tracking at scale has errors, because store pages change and variants get mixed up. When we find a wrong price or a wrong verdict, we correct the page, recompute anything derived from it, and note the fix. If you spot something off, tell us and we'll check the raw record: every published number has one.
Who runs this
Cheaplorer is built and run by Mert G., tracking prices on home tech since 2022. The tracker, the verdict rules and this site are one person's ongoing answer to a simple annoyance: strike-through prices that were never real.