Custom price HTML

function king_custom_price() {
    global $product;

    if ($product->is_on_sale() && is_shop()){

        $regular_price = get_post_meta( $product->get_id(), '_regular_price', true );
        $sale_price = get_post_meta( $product->get_id(), '_sale_price', true );

        return '<del>from '.$regular_price.'</del><ins> '.$sale_price.'</ins>';
    }
}

add_filter( 'woocommerce_format_sale_price', 'king_custom_price', 10, 2 );