Hi, Travelling to London for 3 days at the end of May. I wish to get a tube pass. I have booked a ho ho 48hr bus pass but would like tube access tube. It is suggested on some websites to get a £20 Oyster card but that would be £80 for the four of us. Seems steep. Or is it best just to get a travel card each of the days as they are under £8.00 each per day so total would be £ 64.00 . I only looking for zones 1-2 and not interested in any associated offers. Or is it okto buy a cheaper Oyster. Just a bit confused on which way to play it. Thanks.