Hi Muriel ,
There are two ways you can create such an offer:
1/ Use the WPC Frequently Bought Together plugin. Set the product 2 as the main one and add the product 1 as the Bought Together item in the Bought Together tab of the Product Data section of product 2. Enter the new price for product 1 as “80”, enter “10” to make a 10% discount on the product 1 (main product). This discount percentage will be calculated only when customers choose to buy the Bought Together item (product 1) alongside the main product (product 2).
You can learn more about this plugin here: https://doc.wpclever.net/woobt/
2/ Use the WPC Composite Products to create a new product for both subproducts above. Create a Samrt composite with 2 components. Component 1 adds the product 1, New price = “80”. Component 2 adds the product 2 and enter the new price = “90%” to offer 10% discount on this item.
In the Pricing method, choose Exclude base price. Go to the General tab to enter any number there to add a price for the main composite to be valid and purchasable, so the add to cart button can be displayed (this is required by WooCommerce).
You can learn more about this plugin here: https://doc.wpclever.net/wooco/
Best regards.