https://woocommerce.com/products/woocommerce-cost-of-goods/

Gives you vital information about your business – adds information about store profit and most profitable products so you know about more than just revenueAdd a Cost of Good to each product (including variations!) to always know total costs of products sold in each orderApply costs to previous orders (placed before installation) after you set product costView profit and cost by date range, by product, or by product categoryExport profit / cost report data to CSVInclude costs in orders exported with Order/Customer CSV Export SuiteInclude costs in orders exported with Customer/Order XML Export SuiteCompatible with Product CSV Import SuiteEdit line item costs for editable ordersGain insight into your most profitable and least profitable sellers so you know where to focus your marketingSee a total inventory valuation based on retail prices or cost of goods.Quickly view costs next to prices in your product manager table display

Changelog

* Fix - Make sure order object is available before querying items to set costs