1. A travelcard will cover any journeys made within the zones it covers, e.g. if you buy a zone 1-3 travelcard it will cover any journeys within zones 1-3, but will not cover zones 4 onwards. (Similarly if you bought a zone 2-3 travelcard it wouldn't cover either zone 1 or zone 4 outwards.)
2. There's no limit on how many tube journeys you make, the only limit is how long the travelcard lasts for. All bus travel is also included in a regular travelcard! (And if you were only taking buses, you could get a cheaper bus-only travelcard)
3. Travel in zone 1 is only included if you buy a travelcard which specifically says it covers that zone, i.e. a zone 1-2 or zone 1-3 card would be what you'd have to purchase if you're living either in zone 2 or zone 3 respectively.
4. You should only have to budget for extra one-off journeys you make outside of your regular travelcard zones - these charges are called extension fares, but unless you're planning to make a lot of extra trips further out in London you shouldn't need to worry about it too much.
5. Yep! And the full list of prices is available here:
http://content.tfl.gov.uk/18-plus-student-2018.pdfIt's worth noting that in order to get the 18+ travelcard prices, you first have to apply for an 18+ oyster photocard - travelcards can then be purchased and loaded onto the photocard. The application fee for the card is £20; the applications are currently on hold over August and will be re-opened in September. Once you've applied, you'll need to wait for your university to approve the application and confirm the course dates, the photograph needs to be approved, and then the card needs to be printed and posted out to you; this usually takes around 2 weeks. To apply:
https://photocard.tfl.gov.uk/A few tips:
-If you happen to rent somewhere where your nearest tube station is a multiple-zone station (i.e. it's shown on the map as being on the border for the zones), then you can purchase a travelcard which doesn't have to cover the further away zone. North Acton is a good example - it's a zones 2/3 station, so if you commute from a station like this into central London you can purchase a zone 1-2 travelcard, rather than a zones 1-3 card.
-If you also have a 16-25 railcard then you can link this to an 18+ photocard to get 1/3 off on off-peak PAYG fares. This could be useful if you ever have a period of time when you don't need to commute in every day; in that sort of situaiton, it's likely to be cheaper to pay for single journeys instead of a travelcard!
If you have any other questions feel free to ask - I've regularly commuted and travelled around various places in London for uni the past couple of years, and I actually work for the photocards department at the moment so 18+ discounts are something I'm very familiar with!
