Is there a token for base url?
No, there is no token for base URL is available in civicrm. If you want to use base URL in templates, you can try this:

 // Declare $config;
 $config = &amp; CRM_Core_Config::singleton();

 $baseUrl = $config-&gt;userFrameworkBaseURL;


This will gives you base URL and use variable "$baseUrl" in your template.

Another way is, you can create your custom token for base URL.Refer following link:
http://wiki.civicrm.org/confluence/display/CRMDOC/Customized+%28and+Custom%29+Tokens