'Free' level does not display on the checkout page...

I have only one paid level set up, but the 'free' level is not displaying on my /pro-sites/ checkout page, ie I don't see the "No thank you, I will continue with a basic site for now" text anywhere - just the single 'pro' level I have set up, with the paypal checkout button.

I have free trials disabled - I only want two user types, free (unlimited) and pro (1 year). Am I misunderstanding something? Is a 'free' level only applicable when free trials are enabled??