Oyster card - confusion please help clarify :)
we're going to London in a couple of months.
1) Should we purchase the Oyster card from the US or at Heathrow? We will stay near Earl's Court. We'll just take the Tube to go to major attractions downtown London if we can't walk there. The farthest we'd go is the Harry Potter studios by train from West Brompton [WBP] to Watford Junction [WFJ].
2) Can we buy this card from a ticket agent window or only machines? I'm very concerned our US credit cards will be denied (I know they're not accepted in France because they do not have a Pin #.
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