There's a street in Bangalore where people sell old books by weight[1]. Usually, it's full of old cheap textbooks sold off by students, outdated magazines (like Readers Digest) and such. I spent a cool day walking through, random sampling the piles of books and found a copy of PG's On Lisp in mint condition.

[1] https://www.google.co.in/search?tbm=isch&q=avenue+road+Banga...