Yes, You can. When it's exceeded, you will get notified by email so you can either let it go or disable your account temporarily.

You can login to your Control Panel, then click on the "SETTINGS" menu, and then click on the "Account Settings" submenu, then tick the "Data Transfer Limit" to limit the data transfer and/or tick "Email reminder if data transfer limit exceeded" to get email notification and/or "Suspend account if data transfer limit exceeded" to disable account temporarily and finally click "SAVE" button to process your request.