When we went, the cost of a day pass on the Tubes was about 3 pounds. We went from the station, which was within walking distance to our hotel, to the west end in about 20 minutes, A taxi costs about $15 US and took 1 hour!
Harrod's is a huge shopping experience with floors upon floors of very unique items. We spent four hours wandering through the store. It was very magical.
We went to King's Road, Covent Gardens, Trafalgar Square and rode double decker buses. It was very beautiful.