2 for 1 deals and rail pass
 

My husband and I will be going to London in October and I'm currently gathering as much info as possible. My questions are as follows: Can I purchase an Oyster card ahead of time? How long would it be valid for? Also, would the Oyster card still qualify me for the 2-for-1 entry discounts or do I need to use the National Rail?

This will be my first time in London, and I appreciate your help and ideas.

How long will you be in London? Will make a difference what you put on the Oyster.

Sorry, we'll be in London for 7 full days with an occaisional excursion to Brighton, Bath or Stonehedge.

Oops, I meant Stonehenge :)

It's pretty easy to buy the tube pass when you get to London. You can buy it at the first tube station you come to. You will want a 7 day travelcard loaded onto an Oyster card. Because you are getting the travelcard, you won't have to pay a 3 pound deposit for the Oyster. If you get the 7 day, it will be valid for the 7 days. You can keep the Oyster card for future visits and load more travelcards or cash balance onto it.

As for the 2-for-1 deal, it is my understanding that you can use an Oyster that has a 7 day travelcard on it. I think you need to present the receipt for the Oyster card purchase along with the Oyster. I haven't done this myself, so this advice is worth what you paid :)