How do the Oyster cards work?

Related questions

1. Can you redeem Oyster cards?
2. What is the difference between an Oyster card and a Visitor Oyster card?
3. Can I charge my Oyster card online?
4. How do I get my deposit back on my Oyster card?
5. Can you get money back from an Oyster card?
6. Does an Oyster card expire?
7. How can I check the balance on my Oyster card?
8. Does a Visitor Oyster card expire?
9. Can you buy an Oyster card at the station?
10. How do you put money on an Oyster card?

Tags

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2. #transport
3. #yellow
4. #smartcards
5. #travel
6. #enter
7. #journey
8. #london
9. #gates
10. #public
11. #contactless
12. #payment
13. #oyster
14. #electronic
15. #cheapest
16. #reader
17. #touch
18. #visitor