Market-based visas will affect migrants both who successfully crossed into the US and those who failed along the way. As noted before, black markets tend to segregate participants into clear 'winners' and 'losers'. Winners earn above market rates, and losers are victimized with virtually the entire spectrum of human suffering and misery. Markets, by contrast, tend even out results, and money paid tends to be proportional to benefits gained. Thus, the biggest single gain from moving to market-based visas will be a massive reduction in harm to those who failed to enter the US.
Migrants who failed to enter the US
Market-based visas end predation first by taking migrants out of risky situations, and second, by facilitating protection by the authorities. Thus, for example, in a market-based system, a migrant would have no incentive to come through the desert. A visa could be purchased at any time, and if the visas were sufficient to cover the market, then employment without a visa would become problematic. Therefore, we would expect desert crossings to fall by 95% or more, and trans-Mexico crossings to fall by perhaps 80% (some Central American migrants would still seek to work in Mexico, not the US).
Rapes should accordingly fall by 99%, as women gain a ready, controlled way to enter the US. Kidnappings and extortion of migrants should fall by 90%. Assaults and robberies should fall by 85% or so, as migrants are able to use modes of transportation with both the protection of large numbers of passengers and which are protected by police.
The number of deterred crossers should fall to near zero, as migrants will either have the funds to buy a visa, or they will not. If they do not, coming to the US will make little sense, as there will be few jobs on offer.
Arrests at the border should fall by perhaps three-quarters, but probably not more. In a market-based system, dangerous criminals will be excluded from those eligible for visas. This group, about 20,000 persons per year, will continue to try to cross through the desert. The number of drug smuggling events should fall accordingly, with the proviso that these volumes are likely to find their way into the US through different routes.
And of course, border removals should drop from around 500,000 to perhaps 30,000 for the US and Mexico combined.
Overall, a market-based visa program should reduce adverse migrant events by perhaps 90%, or a bit more with some luck.
Migrants working in the US
As noted before, the average migrant already resident in the US is likely to be indifferent between a visa fee of $3.50 and the current state of affairs. Again, however, black markets tend to produce a wider range of winners and losers. For those earning below the median, a market-based structure will prove a big step up. Further, the market price of the visa, as it is set by the marginal migrant, should be substantially lower than the visa value, in which event perhaps three-quarters of migrants will be better off.
Even for those who see a higher net burden -- and these will tend to be those with the most stable employment -- should benefit from increased earnings opportunties. A study conducted five years after the Reagan amnesty of 1986 showed that those who had received amnesty had been able to step up materially in their careers and earnings. We should see a repeat of such an outcome in this case as well.
Most will benefit
Overall then, virtually all of those seeking entry into the US for work should benefit from a visa system. Perhaps three-quarters of those already working in the US should benefit, and a majority of the remainder should benefit over the following few years. In the end, well over 90% of current and future migrants should benefit from a market-based visa system.