How the ranking works

Every consumable listing gets one figure: price ÷ total weight, in pounds per kilogram. Resin uses pounds per litre, treating 1 kg as 1 litre, which is how the trade quotes it.

Bundles count at their total weight

A listing advertised as "4 × 1 kg" is counted as 4 kg. This matters more than it sounds: multi-spool bundles otherwise look expensive next to singles, and they are frequently the best value on the page.

Discounts are measured against a 90-day average, not RRP

The discount percentages come from comparing the current price with the product's own average over the past 90 days. That is a far more honest baseline than a manufacturer's list price, which sellers can set wherever they like.

Amazon Warehouse listings have no percentage

Warehouse stock — Amazon's own returned and open-box items — carries no 90-day average, because the item has usually never been sold at that price before. We show those as Warehouse deals without a discount figure rather than inventing one.

When we show nothing

If a title does not state a weight we can trust, the per-kilo column stays blank and the listing sorts below everything that does. We would rather show a gap than a number we cannot stand behind.