Gary Becker thinks the US should charge immigrants $50,000 for entry (HT: Trade Diversion).
Makes sense to me. Poor people want to move to rich countries. Rich people don't want them to (except maybe the liberal elites).
And that is because the price of immigration is set artificially at zero. Presumably there is a positive price at which there is positive (i.e. larger than at present) immigration and in which there is a clear pareto improvement for everyone.
Most of the HUGE gains from immigration go to the poor, so why not allow them to choose to pay a bit of those potential gains in order to gain passage? So long as this is enough to compensate any labour-market losses of natives.
This of course assumes some kind of functioning credit market. And some way of allocating those entry fees to those most disadvantaged by the increased immigration (i.e. those with a similar skills profile to the immigrants).
HT: White African for the link (which I've lost) to the info-graphic