Many public libraries have sets of Child; the main one here in Sheffield, for example, and the University library too, of course.  Inter-library loans, if you're in the UK, would work; other countries have similar arrangements.  I managed to scan the first two volumes and put image files on CD from library copies, but finally got myself a set of the Dover reprints at a good price from a secondhand bookshop in Australia.  Shipping to the UK cost almost as much as the books, but it was still a bargain compared to the usual prices they go for.  A Dover set can be as much as $750 -£520 or so- or more, but they do turn up at affordable prices from time to time if you check the listings regularly.  http://www.bookfinder.com/  is probably the most useful search facility, as it checks a number of online catalogues including Advanced Book Exchange, Bibliofind and so on.

Malcolm