以下代码将在有针对性的付款方式下向购物车提供2％的折扣只能由用户用户在结帐页面上选择：

The following code will apply a discount of 2% to cart when a targeted payment method has been selected by a subscriber user role only on checkout page:

// Applying conditionally a discount
add_action( 'woocommerce_cart_calculate_fees', 'discount_based_on_user_role_and_payment', 20, 1 );
function discount_based_on_user_role_and_payment( $cart ) {
    if ( is_admin() && ! defined( 'DOING_AJAX' ) )
        return; // Exit

    // Only on checkout page for 'subscriber' user role
    if ( ! ( is_checkout() && current_user_can('subscriber') ) )
        return; // Exit

    // HERE Below define in the array your targeted payment methods IDs
    $targeted_payment_methods = array( 'paypal', 'stripe' );
    // HERE define the percentage discount
    $percentage = 2;

    if( in_array( WC()->session->get('chosen_payment_method'), $targeted_payment_methods ) ){
        // Calculation
        $discount = $cart->get_subtotal() * $percentage / 100;
        // Applying discount
        $cart->add_fee( sprintf( __("Discount (%s)", "woocommerce"), $percentage . '%'), -$discount, true );
    }
}

// Refreshing totals on choseen payment method change event
add_action( 'woocommerce_review_order_before_payment', 'refresh_payment_methods' );
function refresh_payment_methods(){
    // Only on checkout page
    if ( ! ( is_checkout() && current_user_can('subscriber') ) ) return;
    // jQuery code
    ?>
    <script type="text/javascript">
        (function($){
            $( 'form.checkout' ).on( 'change', 'input[name^="payment_method"]', function() {
                $('body').trigger('update_checkout');
            });
        })(jQuery);
    </script>
    <?php
}

此代码在活动孩子的function.php文件中显示主题（或活动主题）。经过测试并可以正常工作。

This code goes on function.php file of your active child theme (or active theme). tested and works.

所需的付款方式ID ，您将必须使用浏览器检查器工具检查围绕付款方式单选按钮的html代码：

To get the correct desired Payment methods IDs, you will have to inspect the html code around the payment methods radio buttons searching with your browser inspector tools: