Display, in administration product page, a custom meta filed for the product cost price.

The following code must be added to the function.php file of the theme (better if is a child-theme). Optionally you can create a custom plugin.

/**
 * Add cost price column title to admin product list, after the price column
 */
function al_wc_add_column($columns){
    $new_columns = array();
    foreach( $columns as $key => $column ) {
        $new_columns[$key] =  $columns[$key];
        if( $key === 'price' ) {
            $new_columns['cost_price'] = __( 'Cost price','ego-wc-fs');
        }
    }
    return $new_columns;
}
add_filter( 'manage_edit-product_columns', 'al_wc_add_column', 11 );

/**
 * Add cost price column data to admin product list, after the price column
 */
function al_wc_product_column( $column, $postid ) {
    if ( $column == 'cost_price' ) {
        echo get_post_meta( $postid, 'cost_price', true );
    }
}
add_action( 'manage_product_posts_custom_column', 'al_wc_product_column', 10, 2 );

/**
 * Add the cost price meta data to the admin product page
 */
function al_wc_product_meta_cost_price() {
    woocommerce_wp_text_input( array(
        'id'    => 'cost_price',
        'class' => 'wc_input_price short',
        'label' => __( 'Cost price', 'ego-wc-fs' ) . ' (' . get_woocommerce_currency_symbol() . ')'
    ));
}
add_action( 'woocommerce_product_options_pricing', 'al_wc_product_meta_cost_price' );

/**
 * Handle the cost price data saving
 */ 
function al_wc_save_product( $product_id ) {
     if (wp_verify_nonce($_POST['_inline_edit'], 'inlineeditnonce'))
        return;

    if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE )
        return;
    
    if ( isset( $_POST['cost_price'] ) ) {
        if ( is_numeric( $_POST['cost_price'] ) )
            update_post_meta( $product_id, 'cost_price', $_POST['cost_price'] );
    } else delete_post_meta( $product_id, 'cost_price' );
   
}
add_action( 'save_post', 'al_wc_save_product' );

Accolore

Web developer, Wordpress enthusiast, father of two splendid girls.