Advices!

Hello, I'm a Colombian citizen looking for something to do next year, since I found out that moving to the country that I wanted is almost impossible, I'm thinking in going to other places. I've been thinking about travel to Germany in order to learn German, but my budget is not so high, so I was wondering if someone can recommend me a cheap school or a cheaper way to learn.

Because I'm Colombian, I can't just travel there to check for schools, I have to have already one before I apply to the student visa, and then, depending on the answer, I can finally move there.

I need advices about cities, jobs, accommodation and of course schools.

The cheapest way, because it doesn't incur travel and accommodation cost, would be to learn German in your country - e.g. at the Goethe institute.
In Germany, Volkshochschulen and some universities offer cheap full-time language classes, at something like 600-800/month. On top of that, you need 800-1200/month for food and accommodation, and of course the flight ticket.