sale_price

`sale_price` is the single most misused field in promotional catalogs. The pattern that works: set sale_price only when there's an active promotion, pair it with `sale_price_effective_date` to mark the window, clear both when the promotion ends. The pattern that fails: leave sale_price set permanently as a marketing tactic — channels treat permanent sale_price as "this is always discounted" and dampen the urgency signal, suppressing the listing's eligibility for promo-tag placements.

Channels show strikethrough pricing only when sale_price is genuinely a discount from price. The minimum effective discount is around 5% — below that, the visual strikethrough doesn't render in most placements because the difference isn't compelling. The maximum sensible discount before triggering "suspicious price" classifiers is roughly 70-80% — anything more dramatic gets flagged for counterfeit or pricing-error review.

The operational discipline that pays off: schedule promotional pricing via sale_price_effective_date rather than manual flipping. Load BFCM discounts into the feed two weeks in advance with the date range set; let the date control activation; don't rely on someone updating the feed at midnight on the start date. This separates the promotional plan from the execution, which means promotional plans actually happen as planned.