Disable "add to cart" for Guest User

Question

How can I Disable the "add to cart" when user is not logged in.

Answer 1

Please check with below module, which is provide to not login user hide product price.

https://github.com/Tartilas/Magento-hideprice

Also if you want to do via pragmatically than check with below event. Using below event to set price equals to zero

first event :

<catalog_product_get_final_price>
           <observers>
             <hideprice_catalog_price_observer>
               <type>singleton</type>
               <class>Wsc_Postcode_Model_Observer</class>
               <method>hidePrice</method>
             </hideprice_catalog_price_observer>
           </observers>
         </catalog_product_get_final_price>

second event :

<catalog_product_collection_load_after>
  <observers>
    <hprice_catalog_price_observer>
      <type>singleton</type>
      <class>Wsc_Postcode_Model_Observer</class>
      <method>hidePriceCatalog</method>
    </hprice_catalog_price_observer>
  </observers>
</catalog_product_collection_load_after>

simply check if user is not logged in (Observer.php) and set final price equals to zero

public function hidePrice($observer){
            $event = $observer->getEvent();
            $product = $event->getProduct();
            if(!Mage::getSingleton('customer/session')->isLoggedIn()){
                $product->setFinalPrice(0);
                $product->setPrice(0);
            }

    }

    public function hidePriceCatalog($observer){
        $products = $observer->getCollection();

        if(!Mage::getSingleton('customer/session')->isLoggedIn()){
            foreach( $products as $product )
            {
                $product->setFinalPrice(0);
                $product->setPrice(0);
            }
        }
    }

And on phtml we can also check :

if($_product->getFinalPrice() == 0 || $_product->getPrice() == 0){
       echo '<span class="login_for_price"><b>Login to See Price</b><br></span>'; return; }

I hope its work for you.

Answer 2

In Magento version 2 you can disable checkout for guest user from admin panel->store->configuration->sales->checkout.