"LSWR Carriages in the 20th Century" is a case in point, it was £999:00 on eBay from a couple of vendors. I then found out that some of the content I wanted had been published in either The Constructor or RM in the early '70s, which I fortunately tracked down on The Magazine Exchange for a couple of quid each (two mag articles). Sometime later I found a copy for £35 in Oxfam Books in Bath, so had it away.