I'm currently on a mission to try and find a way to sail to South America from Europe. I looked into it in the past but didn't really find anything that was not abysmally expensive.
This is more or less in a few lines what I know;
Re-positioning cruises can be found at low prices (apparently), cheapest I found is $800, 21 days at sea expenses not included.
Freights hopping sounds like a good idea but according to what people have told me it's extremely difficult to get on one due to all these new world terrorist laws.
Sailing on a freight by working or paying a fee I hear can be economical - unless you get one of them lines which exploit the idea and charge as much as a cruise ship.
Private owned sail boats, I tried that in Portugal after meeting a sailor - he said it happened, but it could take a long time and was more of a right place - right time thing.
Also Ocean liners, but I haven't really done much research about them as I just found out they existed.
In the archives there is a few threads which talk about this, people who have wandered around in this fashion.
Does anyone have any first hand information or thoughts about this - or know good ways to go around getting on a ship to get from one continent to another. Without breaking an already broken economy that is.
Stay safe and keep peddling.