Sell tickets in build in Helpdesk module

In order to implement such feature you will need one additional plugin - credits. This plugin is free for active customers. You need to install and activate it.

Then in product settings you can setup number of credits. In case customer buy this product then he received defined number of credits.

On Helpdesk tab user will have ability to submit new ticket only if he has credits. User still will be able to see ticket that he opened before. User can not reply to ticket if you close it from admin interface.

Each time user open new ticket it reduce his balance by 1 credit. User can see history of credits use. In comment he will see ticket id.

In this example I assume one ticket cost 1 credits. Number of credits by product you can configure within product settings.

Add this code to site.php file:

$credit_plugin = Am_Di::getInstance()->plugins_misc->loadGet('credits');

Am_Di::getInstance()->hook->add('gridHelpdeskInitGrid', function(Am_Event_Grid $e) use ($credit_plugin) {
    if (!defined('AM_ADMIN')) {
        if ($credit_plugin->balance() <= 0) {
            $e->getGrid()->actionDelete('ticket');
        }
    }
});

Am_Di::getInstance()->hook->add(Bootstrap_Helpdesk::EVENT_TICKET_AFTER_INSERT, function(Am_Event $e) use ($credit_plugin) {
    if (!defined('AM_ADMIN')) {
        $ticket = $e->getTicket();
        $credit_plugin->debit(1, "Ticket #{$ticket->ticket_mask}", $ticket->user_id, $ticket->pk());
    }
});

You can see user credits history and debit/credit manually from admin interface as well. aMember Cp -> Users -> Browse Users -> (edit) -> Credits