functions.php

add_filter( 'woocommerce_cart_item_price', 'wc_cp_empty_composited_item_cart_order_price', 100, 2 );
add_filter( 'woocommerce_cart_item_subtotal', 'wc_cp_empty_composited_item_cart_order_price', 100, 2 );
add_filter( 'woocommerce_checkout_item_subtotal', 'wc_cp_empty_composited_item_cart_order_price', 100, 2 );
add_filter( 'woocommerce_order_formatted_line_subtotal', 'wc_cp_empty_composited_item_cart_order_price', 100, 2 );
add_filter( 'woocommerce_composited_product_price_string', 'wc_cp_composited_product_empty_price_string', 100, 4 );
add_filter( 'woocommerce_composited_item_price_html', 'wc_cp_woocommerce_composited_item_empty_price_html', 100, 4 );


function wc_cp_woocommerce_composited_item_empty_price_html( $price_html, $product, $component_id, $composite_id ) {
    $price_html = '';
    return $price_html;
}

function wc_cp_composited_product_empty_price_string( $price_string, $product_id, $component_id, $composited_product ) {
    $price_string = '';
    return $price_string;
}

function wc_cp_empty_composited_item_cart_order_price( $price, $values ) {
    if ( isset( $values[ 'composite_parent' ] ) ) {
        $price = '';
    }
    return $price;
}