How we pick deals

Most "deals" compare a sale price to a list price the store chose. We don't use that number. We compare the current price to what the product has actually sold for.

1. We record real prices over time

We check prices continuously and keep the history. A product needs at least three weeks of history before we will post it, so we know what normal looks like.

2. We measure against the usual price

The usual price is the price the product has sold at most of the time over the last 90 days, weighted by how long each price lasted. A deal has to be meaningfully below that, by 10 to 15% or more depending on the category.

3. We check it against the recent low

When a price matches or beats its lowest point in 90 days, we label it a 90-day low. Prices that are only slightly below normal rank lower.

4. We screen out fake sales

• Inflated "was" prices. If a store's list price is higher than anything we've seen it sell for, we say so.
• Raise-then-discount. If a price was pushed up in the weeks before a "sale", we measure against the earlier price.
• Endless sales. A price that hasn't moved for weeks is the new normal, not a deal.
• Out of stock. We don't post what you can't buy.

5. We rank what's left

Deals that pass are ranked by the size of the real discount, closeness to the recent low, and how popular the product is. Commission is a small factor in ranking but never decides whether a deal passes.

Prices change

Prices and availability can change after we post. Always confirm the price at the store before you buy.