The best deal for us the first time we went to London was to buy the London Pass without travel option and buy our Oyster cards separately. Our kids were 4 and 7, so the 4 year old got in free everywhere, we bought a child LP for the 7 year old and then 3 audlt LP's for the 3 adult. The three adults bought Oysters with 7 day travelcards loaded and the kids rode free. We absolutely got our money's worth from the LP given the huge number of things we did. We skipped all the free sites and came back the next year, did not buy a LP and did all the free stuff!