Reply To: add a product on the cart to get discount on other category

[Soft79]

1) Create a coupon with these settings:

Discount type: Percent discount
Discount amount: 10
Products: Bag
Categories: Shoes

2) Paste the following snippet in your child theme’s functions.php and replace COUPON_CODE and 123 with the actual coupon code and id of the Shoes-category (you can find the category id by looking at the url of the category’s edit page; look for something like &tag_ID=123 ):

add_filter( 'woocommerce_coupon_get_discount_amount', function( $discount, $discounting_amount, $cart_item, $single, $coupon ) {
  $COUPON_CODE = 'COUPON_CODE'; // replace with the coupon code
  $DISCOUNTED_CATEGORY = 123; // replace with the category that is discounted

  if ( 0 == strcasecmp( $coupon->code, $COUPON_CODE ) ) {
    $cat_ids = $cart_item['data']->get_category_ids();
    if ( ! in_array( $DISCOUNTED_CATEGORY, $cat_ids ) ) {
      $discount = 0;
    }
  }
  return $discount;
}, 10, 5 );

I haven’t tested the snippet, so let me know if it doesn’t work.