Budget Travel - Visit Britain: Homepage for MoneySaving Tips for Visiting the UK on $2/£1

Check out this great resource for the cost conscious traveller/traveler:

http://www.visitbritain.us/things-to-see-and-do/things-to-do-for-people-like-me/budget-travellers/

Mostly for London

www.londonfreelist.com
www.2for1entry.co.uk