I.e the cost per kg of payload shipping from America to Europe in 17th Century vs the cost per kg of payload shipping from Mars to the Earth in 21st Century.
I suspect the Mars in current day is much greater, but ships and crew back then were not cheap.
To look at the human transportation side: This account (http://www.eyewitnesstohistory.com/passage.htm) by a German who traveled to the new world in the 1750s is harrowing enough, but the way the cost of passage is paid is horrifying, even heartbreaking: He writes of indentured servitude in the same language one would describe slavery (servants are "sold") and often parents would sell their children in the new world to pay for the voyage, not seeing them again for years, if ever.
We could try to bring this into modern terms by multiplying the US federal minimum wage ($7.25/hr * 40 hrs * 52 weeks) by the median indentured servitude (four years) and get $60,320 to take a human across the Atlantic in 1750, but might be painting an apple orange. Still, it gives us at least a very, very rough idea of what a trip to the new world cost then, and a good sense of just how vastly more expensive passage to Mars would cost in the foreseeable future.