Hi Lynx,
The Trevor Thom books are excellent. You could use all of them except book 1 (which covers the flying training itself) and book 5 (which covers the IMC test - I think that's number 5, anyway).
However, I'd recommend that you don't get the R/T one (book 7 I think) - which is uncharacteristically crap. CAP413 is what you should learn your R/T from.
Also, get yourself a copy of the PPL Confuser, which contains sample questions. Study from Thom, then do the Confuser tests to make sure you've learnt the subject well enough before paying for the exams.
I don't know about any specific scheme to borrow or buy books - I'm keeping mine, because they're much more convenient for looking stuff up in than my ATPL notes, as long as the info I need is included in the PPL sylabus, obviously. But people do, from time to time, sell their books, especially if they've decided not to continue flying for whatever reason - you could try advertising on the "wanted" board at your local flying club?
Good luck!
FFF
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