Just got back from one of these used car tents operated by Toyota. They offer a one year warranty, provide financing and you can finance the whole amount for under 4% interest. Of course you pay a premium at these places. But if I find an individual selling a car I want, how do I go about getting the financing set up? I have a work permit and bank statements and all that. My GF could also buy it in her name.

You just contact one of the finance companies to arrange, AIG being one of the most well known. Your gf will need to do it all unless you speak very good Thai, but its pretty straight forward.

If its like a new car, then she'll need an income of around 200% of the monthly payments.