Cart item discount based on quantity in Woocommerce 3

Question

My WP site sells customized t-shirts. The customization plugin makes each customized shirt a line item in the woocommerce cart. If there are 2 shirts ordered of one design (quantity of 2 on that line item) I want to discount. But if there is just 1 item per line I dont want to discount.

I found this solution

Adding a discount by cart items conditionally based on the item quantity

But this seems to change the product price in the db, so after the discount kicks in for say 2 blue shirts because there were 2 ordered on 1 line, if I add a 3rd shirt on a separate line it also gets the discount, which I dont want.

Sorry, but the linked code does not change the product price in the database… It only make calculations based on cart items from the product price, to set a calculated discount (a negative fee) globally on cart. — LoicTheAztec
But what I found when I ran the code is that if I added a 3rd blue shirt as another line item after the 2 item line was properly discounted the newly added shirt was also discounted, which I dont want. — 1amdadmt
This code doesn't add any item in cart… It just make a discount using the Cart Fee API… Your problem is surely due to some other code snippet or a plugin, that is making that. — LoicTheAztec
You are right, I referenced the wrong code snippet,this is the code snippet I tried stackoverflow.com/questions/42135852/… — 1amdadmt
Same thing for this new linked code… It doesn't change the product price in database, it just change the price of the cart item, and doesn't add any cart item either. Now since woocommerce version 3.1+ this code doesn't work anymore, and this need to be done differently. — LoicTheAztec

LoicTheAztec LoicTheAztec · Accepted Answer · 2018-08-24T23:24:52

Since woocommerce version 3+ the linked answer code doesn't work. It needs something different and can even be done in a better way.

The code will apply a cart item discount based on the cart item quantity. In this code example, it will apply a discount of 5% on the cart item, when the quatity is equal or more than 2 (two).

The cart item unit price displayed is always the real product price. The discount will be effective and displayed on the cart item subtotal.

Additionally the product name will be appended with a discount mention.

The code:

add_filter('woocommerce_add_cart_item_data', 'add_items_default_price_as_custom_data', 20, 3 );
function add_items_default_price_as_custom_data( $cart_item_data, $product_id, $variation_id ){
    $product_id = $variation_id > 0 ? $variation_id : $product_id;

    ## ----- YOUR SETTING ----- ##
    $discount_percentage = 5; // Discount (5%)

    // The WC_Product Object
    $product = wc_get_product($product_id);

    // Only for non on sale products
    if( ! $product->is_on_sale() ){
        $price = (float) $product->get_price();

        // Set the Product default base price as custom cart item data
        $cart_item_data['base_price'] = $price;

        // Set the Product discounted price as custom cart item data
        $cart_item_data['new_price'] = $price * (100 - $discount_percentage) / 100;

        // Set the percentage as custom cart item data
        $cart_item_data['percentage'] = $discount_percentage;
    }

    return $cart_item_data;
}

// Display the product original price
add_filter('woocommerce_cart_item_price', 'display_cart_items_default_price', 20, 3 );
function display_cart_items_default_price( $product_price, $cart_item, $cart_item_key ){
    if( isset($cart_item['base_price']) ) {
        $product        = $cart_item['data'];
        $product_price  = wc_price( wc_get_price_to_display( $product, array( 'price' => $cart_item['base_price'] ) ) );
    }
    return $product_price;
}

// Display the product name with the discount percentage
add_filter( 'woocommerce_cart_item_name', 'append_percetage_to_item_name', 20, 3 );
function append_percetage_to_item_name( $product_name, $cart_item, $cart_item_key ){
    if( isset($cart_item['percentage']) && isset($cart_item['base_price']) ) {
        if( $cart_item['data']->get_price() != $cart_item['base_price'] )
            $product_name .= ' <em>(' . $cart_item['percentage'] . '% discounted)</em>';
    }
    return $product_name;
}

add_action( 'woocommerce_before_calculate_totals', 'custom_discounted_cart_item_price', 20, 1 );
function custom_discounted_cart_item_price( $cart ) {
    if ( is_admin() && ! defined( 'DOING_AJAX' ) )
        return;

    if ( did_action( 'woocommerce_before_calculate_totals' ) >= 2 )
        return;

    ## ----- YOUR SETTING ----- ##
    $targeted_qty = 2; // Targeted quantity

    // Loop through cart items
    foreach ( $cart->get_cart() as $cart_item ) {

        // For item quantity of 2 or more
        if( $cart_item['quantity'] >= $targeted_qty && isset($cart_item['new_price']) ){

            // Set cart item discounted price
            $cart_item['data']->set_price($cart_item['new_price']);
        }
    }
}

Code goes in functions.php file of your active child theme (or active theme). Tested and works.

To display the discounted product price instead of the original product price, just remove woocommerce_cart_item_price() function (and hook)…

Newest similar: Cart item quantity progressive percentage discount in Woocommerce 3

Cart item discount based on quantity in Woocommerce 3

1 Answers