The information in that article is incorrect. The Café at Google Campus is (and has always been) free to use, although the tea and coffee is indeed paid separately. Alternatively you can pay to become a 'Resident' on the other floors where you can enjoy free tea and coffee.
I think the author was hoping to encourage startups out of the free seats! ;)
As mentioned above, the cafe is free and run by Central Working. You can use it Monday to Friday, 9am - 6pm. You get free wifi. You have to pay for coffee, but it is very good (provided by Dose Espresso, who use Square Mile Roasters).
TechHub (who run 1st and 2nd floors) offer resident or flex membership. Flex gives you access Monday - Friday, 9am - 8pm. Resident gives you 24/7 access with your own desk. Everybody gets free coffee and toast.
3rd floor changes from month to month, but doesn't usually offer coworking.
Seedcamp are on the 4th floor. Obviously, you only get to use that space if you have been accepted into Seedcamp.
I think the author was hoping to encourage startups out of the free seats! ;)
[1] - Campus London FAQ - http://www.campuslondon.com/faq/
[2] - Campus London Price List (managed by TechHub) - http://www.techhub.com/blog/types-of-membership/