Let's use your $30 per year (it's too low, but for the fun of it, let's use it).
Multiplied by 320,000,000 people, that's an increase of $9,600,000,000.
Wanna add amounts also for hotel work and a lot of other low-skilled work? You could reach $15 B easily. You will say that compared to $17 trillion, or to the cost of the invasion of Iraq, it's not a big amount. I will totally disagree.