Original cost.  

All the original catalogs,...
All the original catalogs, price sheets, renderings, and old photos that you could ask for from Bernard Pedersen and Son:
http://www.bernhard.dk/BPS_Furniture/index.html
I believe Grandson even posts here every now and then.
Myself, I am a proud owner of a BPS teak credenza 188 and hutch 160, and found their site to be very informative and interesting.
If only every Danish furniture family would have documented their business and products so well. . .
The running thread for BPS is here:
http://www.designaddict.com/design_addict/forums/index.cfm/fuseaction/th...

I know the Moller chairs
were under $30 each new.

And
the J39 chair by Borge Mogensen which debuted in 1947 was---I think---about $8 U.S. at the time.
So glad I bought a set of twelve back then. (Just kidding. I wasn't born yet.)

2012 dollars = 10 x 1947 dollars.
So Spanky's J39 chairs were priced at the equivalent of $80.

The J39
was originally designed for the masses, so $80/chair isn't far off at all. It's not much more than most chairs at IKEA.

The Peter Hvidt & Orla Molgaard Nielsen Model 130 lounge chair originaly cost £46 upholstered in vinyl or £70 in leather.
I may be wrong but I think £70 was around a months average wage in the early 60's.

.

To adjust for inflation
(in the USA, at least), you can use any of a number of online calculators or go straight to the source:
ftp://ftp.bls.gov/pub/special.requests/cpi/cpiai.txt