Unfortunately, there are no VIRL discount codes at this moment.
I would recommend that to receive notifications and/or to qualify for future promotions or discount codes when available. You can login to your Certifications Tracking System profile at the following link: Cisco - Login
Then you click on "Update Profile", and select "Yes" to receiving emails about Cisco training, certifications, services, special offerings, and events then click "Submit".
So when and if there are VIRL discount offers, you can receive information directly from Cisco.
Finally, if you need more information regarding VIRL. You can check the VIRL FAQ here: https://learningnetworkstore.cisco.com/virlfaq