Before Duncan McAlpine's enormous '90s price guides to British comics there were some earlier, less well-known publications
Here's the earliest one...published by Alan Austin in 1975...this covers US comic distributed in the UK after 1959 (before this distribution was too sporadic or non-existent). For comparison purposes let's track the price of one issues in all these volumes to see how prices changed, let's pick the first appearance of Spiderman in Amazing Fantasy #15 (mint condition) valued at £15.
These volumes seemed to go through a number of editions (hence why the purchase prices vary on these two volumes). This is the 4th edition and is undated.
These volumes seemed to go through a number of editions (hence why the purchase prices vary on these two volumes). This is from February 1979 and Amazing Fantasy is up to £120.
Chronologically next up is Denis Gifford's effort - although his effort is clearly focussed on British comics and should be seen as a pre-cursor for his later catalogues
Alan Austin then came back in 1983 with an updated comic guide. Amazing Fantasy #15 is now up to £300
According to my notes there was another price guide for 1979 (priced at 75p) but I can't seem to identify it - do you have a copy? Are there are other price guides that I've missed? Leave a comment here or on facebook.