How can I configure a fixed amount discount for all the bundles?
By default, the total price of the Frequently Bought Together items is the same price as if they were purchased separately.
However, if you want to encourage your customers to buy the full bundle, you can configure different types of automatic discounts, including a fixed amount discount.
In order to configure it, just go to the app preferences page and look for the 'Discounts' section:
Once inside, check the 'Apply a global discount to all Frequently Bought Together bundles' option and select the 'Fixed amount' discount type:
Then, on the left side, you can configure the minimum bundle amount to apply discounts (zero if you want the discount to apply to all bundles) and the discount amount of the bundle total. On the right side, you can also configure the discount message that will be displayed in the Frequently Bought Together widget. If you want to configure the styling of the discount message, it can be done in the 'Visual preferences' section.
The discounted amount won't be displayed on the shopping cart page (this is a Shopify limitation). To overcome that, you can configure a message that will be displayed on the cart page when the discount is applied. You can configure the message, its position and styling, in the 'Visual preferences' section. For more information, check the related document 'Why are discounts not displayed in the shopping cart?'.