What you need to purchase depends on the situation.
Do I need a bundle if I already have a device/clicker? No, you can just purchase a subscription. Use the Clicker Registration link in BOLT and then click the 'Purchase Subscription' button.
What if I am a new student or an existing student who needs to purchase a clicker for the first time? You will need to purchase a clicker AND a subscription code. They are sold as a bundle both online or at the bookstore.
Where can I purchase a clicker/device and subscription? You can purchase them online or at the bookstore.