This function increases the cart item prices based on the payment method enabled in WooCommerce.

/* Increase cart item prices based on payment method in WooCommerce BEGIN */

add_action( 'woocommerce_cart_calculate_fees','ts_add_discount', 20, 1 );

function ts_add_discount( $cart_object ) {

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

  

$label_text=__("");

$service_charge=0;

    // Mention the payment method e.g. cod, bacs, cheque or paypal

    $cart_total = $cart_object->subtotal_ex_tax;

    $chosen_payment_method = WC()->session->get('chosen_payment_method');  //Get the selected payment method

    if( $chosen_payment_method == "paypal" ){

                  $label_text = __( "PayPal Service Charge" );

                  // The service charge to apply

                  $service_charge=200;        

     }

    else if( $chosen_payment_method == "cod"){

                  $label_text = __( "Credit Card Service Charge" );                   

                  // The service charge to apply 

                  /* $service_charge=3.5;  */

                  $service_charge = (($cart_total / .965) - $cart_total); /* This is dividing to get a 3.5 percent of the price as a fee */

    }

  

    else if( $chosen_payment_method == "bacs"){

                  $label_text = __( "Direct Bank Transfer Service Charge" );

                  $service_charge=100;  

    }

    else if( $chosen_payment_method == "cheque"){

                  $label_text = __( "Cheque Payment Service Charge" );

                  $service_charge=150;

    }

 

    else {

                  $label_text = __( "Credit Card Fee" );

                  $service_charge=0;

    }

        

     // Adding the service charge

        $cart_object->add_fee( $label_text, $service_charge, false );    

}

add_action( 'woocommerce_review_order_before_payment', 'ts_refresh_payment_method' );

function ts_refresh_payment_method(){

    // jQuery

    ?>

    <script type="text/javascript">

        (function($){

            $( 'form.checkout' ).on( 'change', 'input[name^="payment_method"]', function() {

                $('body').trigger('update_checkout');

            });

        })(jQuery);

    </script>

    <?php

}

/* Increase cart item prices based on payment method in WooCommerce END */