We compare product categories (e.g. “fresh milk”), not identical items. Prices are normalized per kg, litre, or piece unless marked “per pack”.
“Typical price” is the median of a chain's observations; “cheaper options” is the 25th percentile - the price below which the cheapest quarter of offers sits.
Travel retail (airports, roadside) is excluded by default. Chains with stale or too little data are not ranked.
Prices are observations for the stated date and may differ by branch.