yireo_bingtranslate_category.php

<?php
// Basic settings
$storeCodes = array('french');
$attributes = array('name', 'description');
$categoryIds = array(4);

// Initialize Magento
require_once 'app/Mage.php';
Mage::app();
Mage::app()->setCurrentStore(Mage_Core_Model_App::ADMIN_STORE_ID);

// Load the category-collection
$categoryCollection = Mage::getModel('catalog/category')->getCollection();
if(!empty($categoryIds)) {
    $categoryCollection->addAttributeToFilter('entity_id', array('in' => $categoryIds));
}

// Loop through the category-collection
$totalChars = 0;
foreach($categoryCollection as $category) {
    $categoryTranslator = Mage::getModel('bingtranslate/category');
    $categoryTranslator->translate($category, $attributes, $storeCodes);
    $totalChars = $totalChars + $categoryTranslator->getCharCount();
}

$costPerCharacter = (float)6000/1000000000;
$translationCost = number_format($costPerCharacter * $totalChars, 2);
echo "Total amount of characters: ".$totalChars."\n";
echo 'Estimated costs USD $'.$translationCost." (".$totalChars." characters)\n";