Let's take a cheap car from the 1960s, an Austin Mini Cooper.
A 1960s Mini Cooper was about 500 pounds. That's 10.000 pounds in today's money.
Today you can buy a Dacia Sandero for 6.000 pounds. That's almost half of a Mini Cooper.
http://www.thisismoney.co.uk/money/cars/article-2232885/Top-...
The current Mini is nothing like the old Mini, it has billions of features more (exactly the point you were making in the original post I replied to).
I can't find any sources, but I strongly suspect that an inflation-adjusted Trabant would be much more expensive than a Dacia Sandero.
Edit: I found some sources which confirm my hunch. A Trabant would be 11.000 pounds today if bought at East Germany prices, and 5.500 pounds if bought at West Germany (subsidized) price. The same source says that the Mini destroyed the Trabant market, they competed at similar price points.
A Maruti 800, which would be a much better comparison to the 60s Mini or Trabant, should probably cost about 4000 pounds in the U.K.
Source for Trabant prices:
http://heinkelscooter.blogspot.com.uy/2014/01/trabant-east-g...