Historical guide prices

[DougB 0]

After being taken in by a couple of real duds, I swore I'd stay away from E-Bay.  However, despite my resolutution I found myself poring over the listings last weekend and I've picked up a nice sixpence at a fair price.  The interesting point is the provenance of the coin.  It was purchased by the seller on 6/10/1977 from Seaby's of London as UNC for £20.

This raises the question, how would one go about determining the historical guide price of a coin in a particular year?  Is there an online resource or does one simply look out for older Price Guides in second hand bookshops?

The coin in question :

 

[Rob 3,152]

Pick up a range of past references. Coins of England is in its 51st year, so you can go back to the 60s for that. Seaby's Bulletins go back to the 1920s, or Spink Circulars to 1892. I have a copy of Thorburn's book with prices inked in c1930. Past auction results, there is a large amount of info to be extracted from diverse publications.

Any tickets with the coin? Something saying G130 or G399 possibly?

[DougB 0]

Thanks for the advice Rob. I've just picked up a range of decades of C of E on Amazon for literally pennies.

I have an older ESC where the previous owner has ticked off his collection the book. In consequence, browsing makes me very envious. 

Unfortunately no tickets, but the seller has kindly offered to hunt out the invoice. What's the significance of the G130 / G399?

Edited March 17, 2016 by DougB

[Rob 3,152]

Seaby's Bulletin for March 1977 had one about unc for £15, that for July had one listed as G399, same grade and price, so probably the same coin. If it didn't sell, maybe they upped the price to make people think it was better. Looking at the pictures, aUNC is closer to the mark.

[Mr T 179]

Sometime told about a site that is setting out to do this: http://onlinecoin.club/

See the info on the New Zealand 1933 sixpence for example (at the bottom): http://onlinecoin.club/Coins/Country/New_Zealand/Sixpence_1933/

Unfortunately nothing on British sixpences.