This all sounds like something for nothing to me. A theory that free traders often fall victim to. The woman laid off from the leather car seat factory is less likely to buy a car with leather seats with her lower salary. Of course, this begs the question of her own self-improvement, but free trade has little mention of self-improvement, only cheaper prices. Cloth seats could be fashionable again as the cheap cars all come with leather upholstery.
Well, it is something for nothing. Sort of. The "secret" is that the difference is a result of either technology (advances like the cotton gin and the printing press) that is more efficient or productive, or a result of more intelligent organization (like Wal-Mart having a superior logistics chain). Instead of paying $2.00, and half of it is wasted on non-productive activity, you pay $1.00 for the same thing because it's done better. The difference is used to pay for what would otherwise have been an opportunity cost. It's a net gain.
Everyone who has saved a buck by buying a cheaper leather chair will spend that buck on something else. On the average, a few more cars would be bought, and the laid off worker would be hired at the car factory to meet the demand.
This is the reason the private sector and capitalism is vastly more efficient than government bureaucracy.
To preempt (once again) the argument that Mexico will now have the benefits of productive employment at the factory: yes, but that is only feasible as long as we Americans have our own cost-efficient exports to trade. The end result is that everyone and everything is automatically allocated to where it can meet its best use. In other words, a free market.
I think I've essentially repeated myself four times and it's frustrating.
"This all sounds like something for nothing to me."
No, it is the history of the world. Trade has always increased the wealth of societies. Have you ever read anything by Milton Friedman? I suspect that you have not.
Read the following:
http://www.hooverdigest.org/974/friedman.html
and get back to me.