Cruise ships sometimes have repositioning cruises where they go one way across an ocean to start operating in another region, and they can offer significant discounts. I’m sure there’s cheaper ways but it’s an option.

Well this is just off the top of my head, but… bribe the captain with beer and cooking.

Log

You could find someone planning a sailboat crossing and volunteer to be a crew member using one of the crew finder sites. Although it might be difficult with no experience unless you’re a hottie

I think you can just purchase a passenger ticket on some freight ships. I remember stumbling on the subject on YouTube like 3 years ago. Try doing a search for “passenger on freight ship” into YouTube.

Edit: more like 5 or 6 years ago apparently. I’m old.

Which ocean? Do you care where you start and/or end your journey? Miami to Barcelona is going to be very different than Long Beach to Shanghai.

You can find some repositioning cruises for close to the price of a flight, but you’ll be in a shitty cabin and you would need to get to the departure port.

Many freighters rent cabins for passage. No idea how expensive this is, tho.

Stowaway.

Sometimes ships get sold to another part of the world, like a Mediterranean Ship gets sold to the USA. The cabins for this one way trip are extremely cheap

There’s plenty of free spare styrofoam and plastic in the great garbage patch in the Pacific, I hear that stuff floats…

Join the US Navy. They’ll pay you to cross an ocean on a ship and pay for your college tuition.