magento show custom price based on category

Question

I want to show custom price on product detail page. Based on category id

suppose when I view product A with price 100 and categeory id 1

I want to show its price as 100 + 20

and for category id 2

price as 100

What observer should I use to show different price without changing code?

Answer 1

you can use catalog_product_load_after event to change price in product detail page

<catalog_product_load_after>
    <observers>
        <custom_checkout_observer>
            <type>singleton</type>
            <class>Custom_Custom_Model_Observer</class>
            <method>loadaftercatalog</method>
        </custom_checkout_observer>
    </observers>
</catalog_product_load_after>

In observer.php,

 public function loadaftercatalog($observer)
    {
        $oldprice = 0;
        $product = $observer->getEvent()->getProduct();
        $oldprice = $product->getPrice();
        $newprice = 20 + $oldprice;
        $categoryIds = $product->getCategoryIds();
        foreach($categoryIds as $categoryId){
                if($categoryId == 5){
                    $product->setPrice($newprice);
                }
            }
        return $this;
    }