Charles Kenny entertains the idea:
So, how much could—or should—we charge for the right to live and work in the U.S.? [Gary] Becker suggested the U.S. should let in anyone who can pay $50,000 to Uncle Sam and pass a criminal background check. That may seem like a lot of money, but Miao Chi and Scott Drewianka of the University of Wisconsin estimate (PDF) that, allowing for factors including age and education, the average recent Mexican immigrant with a green card (permanent resident status) earns roughly $20,000 a year more than the average Mexican immigrant without one (on a more limited visa or undocumented). So, allowing for education, the average immigrant from south of the border would recoup that $50,000 in less than three years.
Reihan prefers a competitive bidding system.
The Dish 