Which Parker pen is very expensive?

The Parker Duofold Pen is very expensive, depending on the finish they run from $300 to $20,000

The Parker Duofold Big Red Ballpoint Pen  is approximately $300 while the Parker Duofold 100th Anniversary Fountain Pens are more than $1000.

The Parker Sonnet Sterling Silver Mistral Ballpoint is also expensive going for   about $250.00