Magento get base url

It's easy to get Magento get base url. Just use below code to retrieve base url.

Mage::getBaseUrl('type_of_link', 'secure_or_unsecure');

For example:

Mage::getBaseUrl(); 
// returns http://dltr.org/

Mage::getBaseUrl('web'); 
// returns url defined in system/config/web/(un)secure/base url
// http://dltr.org/

Mage::getBaseUrl('link'); 
// returns url defined in system/config/web/(un)secure/base link url
// http://dltr.org/

Mage::getBaseUrl('direct_link'); 
// same as 'link';
// http://dltr.org/

Mage::getBaseUrl('skin'); 
// returns url set on system/config/web/(un)secure/base skin url
// http://dltr.org/skin/

Mage::getBaseUrl('js'); 
// returns url set on system/config/web/(un)secure/base javascript url
// http://dltr.org/js/

Mage::getBaseUrl('media'); 
// returns url set on system/config/web/(un)secure/base media url
// http://dltr.org/media/

Hope that helps.

Source: Mage.php and app\code\core\Mage\Core\Model\Store.php