TastyPie authentication for pure javascript site
will see basic read only info from the Django API.

It sounds like you probably just want to make those bits of the API publicly available for read-only access, and then not use any authentication method.
As you say attempting to hide a key isn't a sensible way to go, and if there's no kind of user login then you can't really authenticate in any secure way.
I'm using Django TastyPie for my API. I have a completely separate HTML application that my user views and will see basic read only info from the Django API. My question is what authentication method should I use in this situation. The HTML application is technically me not the user and they don't login. The app is not Django but pure javascript, hiding a key or anything else is pointless.