If a bundle's price comes up as zero on your collection pages, the first thing to do would be to disable any Quick Shop functionality to ensure bundles cannot be not added to the cart directly at their displayed price.
Customers should always assemble their bundle on the Bundle page, so unfortunately Quick Shop functionality is not compatible with the app.
Once you have done this, we recommend you speak with your theme developer to find a solution, as collection pages are controlled by the theme rather than the app itself, and the themes will usually look for the lowest priced variant.
You may also want to consider deleting these variants from the backend.
There can be a number or reasons why the bundle price comes up as zero in the checkout.
Bundle Builder needs to process the cart content into a draft order - this crucial step involves splitting a bundle into individual products and determining the final price.
When customers select Paypal or GPay in the cart, this step is skipped and as a result price is incorrect and the individual products will not be added to the order.
This is not to say that Paypal and GPay are completely incompatible with Bundle Builder; but they should only be available in the checkout.
To resolve this issue we suggest removing PayPal or GPay from the cart and only allowing Express PayPal and GPay options once the customer has reached the checkout (at which point the bundle has already been processed into individual products):
Please use our guide to find out if there are any issues with your installations.
You may have set up your discounting rules so that it is possible to create a free bundle.