Sorry for asking such a basic question, but there are so many threads I'd like to be able to recall later (when I have enough money...lol).

How do I bookmark threads?

 

The closest thing to a bookmark (besides through your browser) would be thread subscribing. Click the Thread Tools drop down menu on the right hand side, then select Subscribe to this Thread. I think the default settings will email you when subscribed threads update, but you can disable this in User CP.