If you don't find a solution for this, people are using Order Automator app to add free products based on the order contents. This adds the item after the order (if order contains product X, add product Y).
If you're wanting to alter the cart before checkout, you can use the ajax API: https://shopify.dev/docs/api/ajax/reference/cart
Your developer (or you if you're willing to put in some learning time) can use that to add items to cart based on events, for example if customer adds Product A to cart, then add Product B... or on the click of a button, or on landing on a certain page, etc.
You're welcome, hope it helps.
I'm not sure, Shopify Flow came out after Order Automator I've actually never used Flow, but from what I've seen in the forums it handles various automations.
If you have Flow give that a try maybe it will work for your use case, you could also try posting in the Shopify Flow forum board if you have Flow and it seems like something it could do... but if you are wanting to handle this in the theme / before checkout, your best bet would probably be to hardcode the functionality into your theme.
On our Shopify Expert Marketplace, you can find many trusted third party developers and fr...By Arno Nov 27, 2023
You've downloaded the Search & Discovery app from the Shopify App store, and as you're ...By Skye Nov 8, 2023