In my case, it's about $20,000. $30,000 would enable you to live very comfortably while abroad, I would think. I work at a lowly data-entry night shift job which explains why I make abysmal wages, and also I'm paying for college for the next 2 years. At graduation, I'm aiming for $15,000-20,000 saved up by then.
Depends on where 'abroad' is. If you're coming to Europe it's not much. Also don't underestimate how much COL has risen across the world the last couple of years. Yes you can still live cheap in the countryside of China or Angola, but the 'connected' places across the world aren't that cheap any more.