The NUS Extra cards are the new Student Cards. Yes, they cost £12 - however they entitle you to a lot more than the old Student cards ever did. Online discounts, Alton Towers "Card Holder Only" days, cheap tickets on Ticketmaster, valid ID and much, much more.
Last year 80% of students made their money back, 20% saved over £50, and 84% intend to purchase again this year.
Cards can be bought on line through the remote online ordering service https://cards.nusextra.co.uk/