sharing my experience of buying notes together last year here:
totally 6 persons formed a purchasing group. we bought one original set only. the total cost of purchasement is evenly shared, which includes the photocopy cost of the other five sets of notes.
the major coordinator (the one who organized we six for the purchasement, contacted with the book dealer in Singapore to buy the original version notes and settled the cost sharing issue) got the original set. all other five got the photocopied versions.
I must admit that, if we could find that dealer who are selling the photocopied version, the whole purchasement become much more convenient and cheaper.