Usually, spotify will send an email to notify that your student subscription is about to end in a few days. Click on the link provided in that email that says, "Extend Discount" and it WILL prompt you to go Premium. This may seem confusing since it feels like you are about to pay for a new subscription. However, just make sure you're signed into your own account after you click on the "Extend Discount" link. It will ask you to verify your payment method and what school you're attending. Follow instructions to verify that information. After that, it will confirm that your student subscription has been renewed and that they will bill $4.99 for the next billing period. (if you have already paid $9.99 for this month like i did, it will start billing 4.99 for the next month).