You can subscribe to Elicit Plus from anywhere in Elicit by clicking the upgrade button in the sidebar:

Select the Monthly billing option below the annual billing option. Then click Continue to Checkout.

Once you complete payment, your 12,000 monthly credit allotment will be applied to your account immediately upon upgrade.

You can continue to use your free 5,000 credits if/when you run out of monthly credits. You will also be able to purchase additional top-up credits as needed.

Unused monthly credits do not roll over month to month. On your billing date each month, you account will be replenished to a total of 12,000 credits for the month.