Some books known as "Ladybird Books" by "Wills and Hepworth", going back to the 1940's and only costing about 2s/6d (27 cents), are now worth up to $650.00.

Many a U.K. resident, setting out for Australia on a £10.00 one way ticket, would have probably brought one or more of these small books for their children along with them.

Maybe you've got one or two. Most of the editions from 1940 to 1985 are worth between $11.00 and $650.00 each.