Nothing beats leaving home with enough money for your trip - but non-profit jobs for an international organization may be an option if you need more funds to top up your budget along the way.
Only if you're a skilled professional, however!
Local jobs are held by local people, but occasionally, when staff is not available, an international development job might be up for grabs for a few days, weeks or months - if you're sufficiently qualified.
International charity or NGO jobs usually mean working for either a government organization - like the UN - or a non-governmental organization or charity like Oxfam or the Red Cross.
The United Nations itself has many agencies, funds and programs, each of which recruits individually. This relatively comprehensive list of international organizations may help you get started on your search.
Many short-term charitable jobs abroad are managed from field offices, or local offices that deal with a single country. The same organizations also have regional offices that deal with several countries, as well as world headquarters (where most recruitment takes place for development and humanitarian not-for-profit jobs).
Non-profit jobs in field offices could involve any of the following work:
These jobs usually require both a university degree and significant experience in your area of work. If you're fresh out of school, this won't be the right option for you. You should be looking for student work or seasonal work instead.
Your first step is to be clear about the kind of work you want. You won't get far by walking into an office and asking for 'any kind of work.' This gives people the impression that you have no idea of what they need, that you haven't done your homework.
Worse, they might have to spend time training you instead of getting ahead with their own priorities. So be clear about what they are doing and how you can help them.
You then should look for those non-profit organizations that might employ someone with your skills. Check their website to see if they have an office in the particularly country you're planning to visit - then get in touch.
I've found several short-term local non-profit jobs through word of mouth. Here are some tactics you could use to get closer to your goal:
It won't be easy but there are non-profit jobs to be had out there. You'll just have to look for them as diligently as you'd search for a job back home.