KUMALA

Please use the internet-based book store for any bargain textbooks, now I have some which I used most during my times of studies.
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! p4 f* t4 O. B1 ~" K  @# M! FOne is as-you-mentioned "Second Hand Book Store", please use the link: http://www.abebooks.co.uk (This one really rocks, and I believe it should meets most of your demands. )2 z; b5 x2 e/ E, Q  d8 |4 S4 I. `
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The other one - Amazon, however. It's not always cheaper than Abebooks, but you will find an even wider range of the book selections: http://www.amazon.co.uk5 Q' Z' G, m, R+ s: W( W! Z
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The third one, which I used not that often, as this one actually has the real book stores all around the UK, named Waterstone's: http://www.waterstones.com8 e$ J  i: ~+ |; [6 z, P

( x& L) \- u  U' SBesides, for a postgraduate student, you may not have to purchase every book listed on your reading list, it's just simply because you need to read at least 4 or 5 books for a single course per average. Therefore borrowing from the university library as fast as you can would be even better, yet absolutely cheaper.
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. K4 k9 w& a4 O5 C: k* n9 Z+ [So you don't actually need to walk that far for seeking Bargain shops, everything can be done online.
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- s, S5 ?4 L3 \+ @6 C9 rBest regards