How to redirect user to different thanks page after payment

You can use our thanks-redirect plugin to do it. This plugin allow you to set up custom redirect url for each product in admin interface.

In case you need some more complex logic you can use the following approach:

Create /amember/application/configs/site.php with this code:

<?php
        Am_Di::getInstance()->hook->add(Am_Event::THANKS_PAGE, 'onThanksPage');
        function onThanksPage(Am_Event $event){
            /* @var $di Am_Di */  
            $di = Am_Di::getInstance();
            /* @var $invoice Invoice */ 
            $invoice = $event->getInvoice();
            /* @var $controller ThanksController */ 
            $controller = $event->getController();

            $controller->redirectLocation('/url/where/user/should/be/redirected');
        }
?>