HikaShop App - Problems

/**
     * Retrieve product price
     *
     * @since   2.0
     * @access  public
     * @param   string
     * @return
     */
	public function getProductPrice(&$product)
	{
		$currencyHelper = hikashop_get('class.currency');

		$config = hikashop_config();
		$discount_before_tax = (int)$config->get('discount_before_tax',0);
		$currencyClass = hikashop_get('class.currency');
		$currency_id = hikashop_getCurrency();
		$main_currency = $currency_id = (int)$config->get('main_currency', 1);
		$zone_id = hikashop_getZone(null);
		$ids = array($product->product_id);

		$currencyClass->getPrices($product,$ids,$currency_id,$main_currency,$zone_id,$discount_before_tax);

		$product->price = $currencyHelper->format($product->prices[0]->price_value);

	}

<i class="fa fa-folder"></i>&nbsp; 
            <?php for ($i=0; $i < count($product->categories); $i++) { ?>
                <?php echo $product->categories[$i]->title;?>
                
                <?php if (isset($product->categories[$i+1]->title)) { ?>
                    <?php echo ','; ?>
                <?php } ?>

            <?php } ?>
            </li>