several reasons for that though. I've built up my own private library over the years, long before I went to uni, so I have most of the core texts of my subject already at my disposal. I also shopped around and didn't just put in a bulk order at Waterstones or Amazon. I got one book which normally sells for ~£115 for £10, new and sealed. You just have to plan in advance and compare prices.
The final reason is just the advantage of being in a city with good academic resources for my subject. We have several dedicated libraries and societies, and my university is also very strong on my chosen subject, with a very extensive library collection of it's own.