Or you can do it like this:
Here are the instructions:
---Canceling a Subscription cancels all future scheduled payments of that
subscription. If you would like to cancel a Subscription, please follow
the instructions below.
1. Log into your account at
https://www.paypal.com by entering your email
address and password in the Member Login box.
2. Click on the "History" tab near the top of the page.
3. Choose the "Subscriptions" field from the "Show" drop-down menu.
4. Choose "Past Year" from "For:" drop-down menu.
5. Check the Radio Button for the "For:" drop-down menu.
6. Press the "Submit" button.
7. View the details of a specific transaction by clicking on its "Status".
8. At the bottom of this page, select the "Cancel Subscription" button.
9. On the confirmation page, select the "Cancel Subscription" button
again.
Please note: You may need to cancel a scheduled payment at least one day
prior to the scheduled date of the next payment. Canceling a subscription
on the day of a scheduled payment will not guarantee that the payment will
not be sent.