I need a module that when you add product to cart check two conditions and if they are correct will change the price for the product in the basket.

I need do something like this: - when product is added to the cart - get Qty and custom_attribute of product - if qty<0 and cutom_attribute value for product is >0 change of product price in cart (the changed price should be use in transactional emails, order view, on the invoice etc.)

I try use checkout_product_add_after, but I cannot get product attribute and check condition. How to get custom product attribute in this event?

Maybe should I use another event?

  • What about the weight? Why are you trying to change it? Has it something to do with the shipping costs? And why should the qty be checked for <0 (smaller then 0)? Typo? Because this cries out for a simple cart rule to me.
    – Nicolas
    Commented Sep 19, 2015 at 7:24
  • I have 2 warehouses. First (local) warehouse - if I have product in local warehouse a Qty attribute is more than 0 (Qty>0) Second warehouse - if I haven't product in local warehouse customer can buy the same product (or another) with different price; if order is from the second warehouse the weight must change becouse I have different shipping cost (different product weight and another shipping pricing);
    – gregory
    Commented Sep 19, 2015 at 21:52

2 Answers 2


Try adding an observer for event event 'sales_quote_add_item':


In your observer :

public function updatePrice($observer) {
    $event = $observer->getEvent();
    $quote_item = $event->getQuoteItem();

    $product = $quote_item->getProduct(); //You may need to load the product module or add the attribute to flat table
    $new_price = <insert logic>

See https://stackoverflow.com/questions/9721583/changing-the-price-in-quote-while-adding-product-to-cart-magento

  • I don't think this is going to work unless you enable Super Mode ;) : $quote_item->getProduct()->setIsSuperMode(true); Commented Sep 18, 2015 at 21:12
  • Ok, but when I add some condition under $product = $quote_item->getProduct(); and the condition is false then a shopping cart page is crashed...
    – gregory
    Commented Sep 19, 2015 at 21:53
  • Could you add the code to your question above? Commented Sep 20, 2015 at 12:48
  • This will update the price in database right? What if i only need to change the price in the checkout process (Customer only pays the price i put in the checkout) but the price in the product page remains the same? Commented Jun 17, 2016 at 10:46

I have the same need, that is to say change price as customer is adding the product to his cart. As I'm not accustom to things like $variable->getId() ... I use common PDO queries. I use this event with an observer : checkout_cart_add_product_complete I manage to get the cart, change the price, BUT it is impossible to update table sales_flat_quote_item ! I use this PDO query :

$connexion->exec("update sales_flat_quote_item set price='".$prixHT."', base_price=".$prixHT.", row_total=".$prixHT.", base_row_total=".$prixHT.", tax_amount=".$prixHT*0.2.", base_tax_amount=".$prixHT*0.2.", original_custom_price='".$prixTTC."', price_incl_tax='".$prixTTC."' base_price_incl_tax=".$prixTTC.", row_total_incl_tax='".$prixTTC."', base_row_total_incl_tax='".$prixTTC."' where item_id='".$ligne['item_id']."'");

NO CHANGE into sales_flat_quote_item . If I write the query directly into phpmyadmin, it works ! Why doesn't it work through the observer ? thank you for comments :)

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