It is really amazing the Model T made this list, since the US population in the 1920's was ~106 million, whereas in 2010 it was 308,745,538, or only 1/3 the size. As for prices, general inflation means a $500 price for the (then new) 1927 Model A would now be ~$12,000, compared with the 2006 MSFP of a Ford Focus at ~$15000. Its not really an apple-apple comparison, however, since the 2006 Focus is probably a better car than the 1927 Model A. This is an inflation rate of 1,929% since then. See
http://inflationdata.com/inflation/inflation_rate/long_term_inflation.asp