Scroll down the page if necessary, and look in the lower right area where you'll see the deactivate button:
If you want to maintain access to your account for future use, but no longer want to be charged for your machines, we recommend keeping your account active and simply deactivating the VMs you no longer intend to use. Click here to see how.
Note: if you cancel and then re-activate your Paperspace account, you will not see any machines you created or data stored.
You will be presented with the following pop-up after clicking the "Deactivate" button:
We really appreciate any feedback you can provide so that we can improve the service for everybody!