I did a 18 week welding course (2 hours a week) and loved it.
It was in Gas, Mig and Stick (Arc) welding. I could stick bits of metal together before but very roughly and by the end of the course I was a lot more confident and adept at it.
Think I'll start looking into what my local college does, a few hundred quid is a fair bit of money but for skills that'll last a lifetime...
Welding certainly has a lot of practical applications even if you never do it as a job, there are always going to be people who'll chuck you a few quid for sorting out little things. Or even doing it as a favour, that’s a good way to make friends.
Plumbing would probably be a good skill, even in a country without infrastructure there may be money to be made if you can arrange sanitary disposal of waste or water filtration.