Hey @EFJ9678
Shopify’s native Buy X Get Y discount is a backend discount rule, it can be triggered via discount codes and requires customers to add gift products manually to their cart.
Even for a simple free gift pop up offer, you’ll need a third party app.
I recommend you try Monk, a built-for-Shopify app that can create complex free gift offers including the one you’re looking for: a Free Gift- pop up, triggered when items from a specific category are added to the basket.
A free gift pop-up is recommended when you are offering multiple gifts to the customer to choose from or a gift product that has variations like size, color etc.
For a better user experience and the product to be automatically added to the cart I recommend you set up a Free Gift-Auto Add offer using Monk, which adds the gift product of your choice to the customer’s basket when 3 items from a specific collection is added to the basket.
Monk doesn’t slow down your store, as it does not take over the cart, rather blends seamlessly with your existing Shopify cart. The widgets are fully customizable to match your store’s colors and brand guidelines.