Woocommerce - Mostrar el precio del producto de variación activa

Logré encontrar una solución. Muestra el precio de la variante debajo o junto a los botones de radio.

Mostrar el precio de la variante (cuando se proporciona un ID):

function get_product_variation_price($variation_id) {

global $woocommerce; 
$product = new WC_Product_Variation($variation_id);
return $product->get_price_html(); // Funciona. Usa esto si quieres el precio formateado
}

Encontrar el ID de la variante, enviarlo a la función get_product_variation_price y luego mostrar el precio:

///Mostrar el precio de los botones de radio de la variante seleccionada activamente
$product_variations = $product->get_available_variations();
$arr_variations_id = array();
foreach ($product_variations as $variation) {
    $product_variation_id = $variation['variation_id'];
    $product_price = get_product_variation_price($product_variation_id);
    echo $product_price;
}

El bucle foreach para mostrar los botones de radio:

foreach ( $options as $option ) {
    print_attribute_radio( $checked_value, $option, $option, $sanitized_name );
                                }

Bucle foreach de botones de radio modificado con clave de array

foreach ( $options as $key=>$option ) {...}

Bucle foreach combinado:

foreach ( $options as $key=>$option ) {
    print_attribute_radio( $checked_value, $option, $option, $sanitized_name );
    $product_variations = $product->get_available_variations();
    $variation_product_id = $product_variations [$key]['variation_id'];
    $product_price = get_product_variation_price($variation_product_id);
    printf ('%1$s</div> ', $product_price);
                                    }

Código completo:

<?php
/**
 * Formulario de añadir al carrito para producto variable
 *
 * @author  WooThemes
 * @package WooCommerce/Templates
 * @version 2.5.0
 *
 * Modificado para usar botones de radio en lugar de desplegables
 * @author 8manos
 * Modificaciones adicionales para mostrar el precio debajo de los botones de radio
 * @author GoodGuyTaj
 */

if ( ! defined( 'ABSPATH' ) ) {
    exit;
}
// INICIO obtener precio del producto 
function get_product_variation_price($variation_id) {

    global $woocommerce; 
    $product = new WC_Product_Variation($variation_id);
    return $product->get_price_html(); // Funciona. Usa esto si quieres el precio formateado

}
// FIN obtener precio del producto 


// INICIO Mostrar Botones de Radio
function print_attribute_radio( $checked_value, $value, $label, $name ) {
    // Esto maneja la compatibilidad con versiones < 2.4.0 donde los atributos de texto no se sanitizaban.
    $checked = sanitize_title( $checked_value ) === $checked_value ? checked( $checked_value, sanitize_title( $value ), false ) : checked( $checked_value, $value, false );

    $input_name = 'attribute_' . esc_attr( $name ) ;
    $esc_value = esc_attr( $value );
    $id = esc_attr( $name . '_v_' . $value );
    $filtered_label = apply_filters( 'woocommerce_variation_option_name', $label );
    $super_filtered = explode(' ', $filtered_label);
    printf( '<div><input type="radio" class="radioselect" name="%1$s" value="%2$s" id="%3$s" %4$s><label for="%3$s">%5$s</label>', $input_name, $esc_value, $id, $checked, $super_filtered[0] );
}

global $product;

$attribute_keys = array_keys( $attributes );

do_action( 'woocommerce_before_add_to_cart_form' ); ?>

<form class="variations_form cart" method="post" enctype='multipart/form-data' data-product_id="<?php echo absint( $product->id ); ?>" data-product_variations="<?php echo htmlspecialchars( json_encode( $available_variations ) ) ?>">
    <?php do_action( 'woocommerce_before_variations_form' ); ?>

    <?php if ( empty( $available_variations ) && false !== $available_variations ) : ?>
        <p class="stock out-of-stock"><?php _e( 'Este producto actualmente está agotado y no disponible.', 'woocommerce' ); ?></p>
    <?php else : ?>
        <table class="variations" cellspacing="0">
            <tbody>
                <?php foreach ( $attributes as $name => $options ) : ?>
                    <tr>
                        <td class="label" style="margin-top: -10px;"><label for="<?php echo sanitize_title( $name ); ?>"><?php echo wc_attribute_label( $name ); ?></label></td>
                        <?php
                        $sanitized_name = sanitize_title( $name );
                        if ( isset( $_REQUEST[ 'attribute_' . $sanitized_name ] ) ) {
                            $checked_value = $_REQUEST[ 'attribute_' . $sanitized_name ];
                        } elseif ( isset( $selected_attributes[ $sanitized_name ] ) ) {
                            $checked_value = $selected_attributes[ $sanitized_name ];
                        } else {
                            $checked_value = '';
                        }
                        ?>
                        <td class="value" style="margin-top: -30px;">

                            <?php
                            if ( ! empty( $options ) ) {
                                if ( taxonomy_exists( $name ) ) {
                                    // Obtener términos si es una taxonomía - ordenados. Necesitamos también los nombres.
                                    $terms = wc_get_product_terms( $product->id, $name, array( 'fields' => 'all' ) );

                                    foreach ( $terms as $term ) {
                                        if ( ! in_array( $term->slug, $options ) ) {
                                            continue;
                                        }
                                        print_attribute_radio( $checked_value, $term->slug, $term->name, $sanitized_name );

                                    }
                                } else {

                                    foreach ( $options as $key=>$option ) {
                                        print_attribute_radio( $checked_value, $option, $option, $sanitized_name );
                                        $product_variations = $product->get_available_variations();
                                        $variation_product_id = $product_variations [$key]['variation_id'];
                                        $product_price = get_product_variation_price($variation_product_id);
                                        printf ('%1$s</div> ', $product_price);
                                    }


                                }
                            }

                            echo end( $attribute_keys ) === $name ? apply_filters( 'woocommerce_reset_variations_link', '<a class="reset_variations" href="#">' . __( 'Limpiar', 'woocommerce' ) . '</a>' ) : '';
                            ?>
                        </td>
                    </tr>
                <?php endforeach; ?>
            </tbody>
        </table>

        <?php do_action( 'woocommerce_before_add_to_cart_button' ); ?>

        <div class="single_variation_wrap">
            <?php do_action( 'woocommerce_before_single_variation' ); ?>

            <?php
            if ( has_action( 'woocommerce_single_variation' ) ) {
                do_action( 'woocommerce_single_variation' );
            } else {
                // Compatibilidad con versiones WC < 2.4
            ?>
                <div class="woocommerce-variation single_variation"></div>

                <div class="woocommerce-variation-add-to-cart variations_button">
                    <?php if ( ! $product->is_sold_individually() ) : ?>
                        <?php woocommerce_quantity_input( array( 'input_value' => isset( $_POST['quantity'] ) ? wc_stock_amount( $_POST['quantity'] ) : 1 ) ); ?>
                    <?php endif; ?>
                    <button type="submit" class="single_add_to_cart_button button alt otto"><?php echo esc_html( $product->single_add_to_cart_text() ); ?></button>
                    <input type="hidden" name="add-to-cart" value="<?php echo absint( $product->id ); ?>" />
                    <input type="hidden" name="product_id" value="<?php echo absint( $product->id ); ?>" />
                    <input type="hidden" name="variation_id" class="variation_id" value="0" />
                </div>
            <?php } ?>

            <?php do_action( 'woocommerce_after_single_variation' ); ?>
        </div>

        <?php do_action( 'woocommerce_after_add_to_cart_button' ); ?>

    <?php endif; ?>

    <?php do_action( 'woocommerce_after_variations_form' ); ?>

</form>

<?php do_action( 'woocommerce_after_add_to_cart_form' ); ?>