Hey, good luck there. I learned to fly there and had a wonderful time and good training.
Stick to the club headsets for the time being. They're fine. Even when I was renting for a while, I generally borrowed headsets. A decent headset will cost as much as everything you really do need, all put together.
I disagree with the idea of borrowing books from the library. There's a fair amount of ground school work to do for the exams, and you will want to refer back to them over time. Even today, I always take the air law one with me on the train and revise weather and air law - my 2 unfavourite subjects happily combined into a single book!
I'd get a subscription to airquiz.com. They do single subjects for 3 pounds. Get the aviation law book - they'll want you to have done this exam before sending you solo.
In due course you will also need a protractor, ruler, whizz wheel, set of coloured pens and a kneeboard and a cheap watch. I think that's about it.