Product discounts are line offers. They apply first, before order-level offers and before a coupon.
The discount never exceeds the price of the lines it covers.
When several product-level rules fit the same line, your priority and combining settings decide. See Priority and combining.
In the online store
A product discount on chosen products, categories or brands can show as a badge on the product card. An automatic percentage without a cap, or a per-unit fixed amount, with no other condition can also show the reduced price on the card. Offers with a minimum, a code, a customer limit or a delivery, payment or location condition show as a badge only. See Show the offer in the online store.
Product discount or sale price?
A sale price on the product itself is a catalogue price. A product discount is an offer added on top at checkout. To stop the two from adding up, tick Not products already on sale under Exclusions.