<checkout_cart_product_add_after>
        <observers>
            <priceupdate_observer>
                <type>singleton</type>
                <class>Edge_Package_Model_ObserverPrice</class>
                <method>updatePrice</method>
            </priceupdate_observer>
        </observers>
</checkout_cart_product_add_after>

public function addFreeItems($observer) {
   $quote = Mage::getSingleton('checkout/session')->getQuote();
   //foreach loop
   $quote->addProduct($product, array('qty' => '1', 'product_id' => $product->getId()));
}

请参见/ app / code / core / Mage / Checkout / Model中的方法addProduct /Cart.php

see method addProduct in /app/code/core/Mage/Checkout/Model/Cart.php

请参见 http：// magentocommerce .com / boards / viewthread / 39334