Product cost list

Unit cost is the number shop catalogues lose most often, and the one nothing downstream works without. A missing cost does not read as missing in most reports; it reads as zero, and a zero cost shows you margin you do not have. That failure mode is exactly what Shopify's COGS report keeps out of view, and it is why this file starts from the catalogue rather than from the accounts.

The effective_from column is the quiet star. When a supplier raises prices in February, you add a new row with the new cost and the February date, and every order before it keeps the cost that was true when it was placed. That habit is called effective dating, and it is what stops one price change from rewriting last quarter's margin.

Weight is in the file because carriers bill by it. A missing weight does not make shipping free, it makes the cost wrong, so it belongs in the same file the costs live in, filled once per variant. In nouz the same two values sit on each variant's panel on the Products page, filled in from Shopify wherever your catalogue already carries them, and a value you enter yourself is never overwritten by a later sync. The file is a worksheet to gather them in, and costs from a spreadsheet are typed into nouz per variant.