WooCommerce - Make a set of coupons adding a fixed fee to an order

Question

A client has a very odd request: they would like for a set of coupon codes to add a fee to an the order. Is this possible?

The problem they are tryi

Answer 1

Yes you can do it with that snippet code (for a set of coupons):

function coupon_add_cart_fee( $bookable_total = 0 ) {
    $has_coupon = false;

    // Set here your specials coupons slugs (one by line - last one have no coma)
    $coupon_codes = array (
        'your_coupon_code_slug1',
        'your_coupon_code_slug2',
        'your_coupon_code_slug3' 
    );

    // Set here your fee amount or make fees calculation (see the links in reference)
    $fee = 20;

    if ( is_admin() && ! defined( 'DOING_AJAX' ) )
        return;

    // checking if that "special" coupon is applied to customer cart
    foreach ($coupon_codes as $coupon_code) {
        if ( WC()->cart->has_discount( $coupon_code ) ) {

            // If yes apply the fee to the cart
            if ( !$has_coupon ) {
                $has_coupon = true;
                break;
            }
        }
    }

    if ( $has_coupon ) {
        WC()->cart->add_fee( 'Fees: ', $fee, false );
    }
}
add_action( 'woocommerce_cart_calculate_fees','coupon_add_cart_fee' );

This code is tested and it works. It goes on function.php file of your active child theme or theme.

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TAX OPTIONS with add_fee() method

IMPORTANT: The fact that TAX is working or not with add_fee() method depends first of your tax settings in woocommerce.

Class WC_Cart add_fee() method, adds additional fee to the cart.

add_fee( string $name, float $amount, boolean $taxable = false, string $tax_class = ''  )> <!-- language: lang-css -->

Parameters:
    $name      Unique name for the fee. Multiple fees of the same name cannot be added.
    $amount    Fee amount.
    $taxable   (default: false) Is the fee taxable?
    $tax_class    (default: '') The tax class for the fee if taxable. A blank string is standard tax class.

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Reference:

• Add tax free fees to WooCommerce cart programmatically
• Class WC_Cart - add_fee() method
• Class WC_Cart - has_discount() method