A sale price set for a product variant overrides all other possible group and single product discounts that may apply to the parent-product.
The below instructions presume that you have product variants created in the store as described in Product Variants.
To set a sale price for a product variant:
1. Select a product on a product listing page (Catalog -> Products) in your store Admin area and open the product details page for editing.
2. Open the ‘Variants’ tab for editing.
Here, refer to the “Sale” column to add sale prices to product variants:
3. Set a sale price either in absolute value or in percentages.
4. Click Save changes to submit the new configuration.
The product listing and product details pages in the storefront will display a discount set on the default product variant for products with product variants. The rest of the discounts (if any) will be displayed when viewing the available product variants on the product details page.
Storefront product listing page
Storefront product details page. Default variant.
Storefront product details page. Other variants.