Some stunning stuff you have there.
As for the price of models back then it was not far off compared to what we pay now. There was no such thing as minimum wage in the UK at that point. When i started working the age of 16 i was paid £1.98 an hour. Bear in mind that chaos Dwarves had not been touched as a range for around 4 years so fairly pricey for metals and the plastics where all monopossed kits. Minimum wage here is over 3 times that now, so if anything it could be considered slightly cheaper as a hobby. Now a days i am self employed so basically i decide what i am worth paying. :P