Just go and purchase a cheap phone on arrival. UK phone costs are generally much cheaper than the US because the receiver does not pay anything. There is a branch of “Car Phone Warehouse” in Cornmarket street for example.
I am really not sure a bicycle is a good idea. A student died in a cycling accident in my first few weeks at Oxford and I decided that cycling was not for me. Think about cycling on the other side of the road in very heavy traffic with lots of buses and roundabouts. Unless the student is living very far from the centre (which is pretty unlikely) cycling will probably not be necessary.