
Let's break this down:
Visa Fees
In the 2015 fiscal year,
the US issued roughly 82,000 visas to people from Mexico. The visa fees for immigrant and non-immigrant visitors
range from anywhere between $100 to $800 depending on a host of different factors. In other words, visa fees from Mexicans account for very little US revenue (much, much less than even a billion dollars a year), and the money we'd make from increasing those fees would be offset entirely by the economic damages caused by dissuading tourists and legitimate visitors from coming to the United States and spending money.
Border Crossing Fees
Again, absolutely a drop in the bucket. Any meaningful amount of revenue coming from fees like this would be offset by other economic damages.
Worker Visa Fees
ibid., and see stats under 'Visa Fees'
Foreign Aid Cuts
I love the discussion of cutting foreign aid because it just goes to show how ridiculous master-strategist Annoying Orange's policy really is. Foreign aid to Mexico is very fickle and changes year to year, but it's generally between $200-800 million depending on the political climate (the Merida Initiative appropriated lots of money for Mexico with the goal of combating drug trafficking).
Even the most conservative estimates of the total cost of the 'wall' fall within the tens of billions of dollars. If someone went up to you and said, "Hey, pay us
billions of dollars for this ridiculous border wall, or we're going to cut
millions out of your aid package," would you agree to that?
Tariffs
We have an entire trade agreement (NAFTA) created to remove tariffs between the US and Mexico. The largest market for crops from southwestern states is Mexico, and adding tariffs would devastate those economies. Congress would not approve trade barriers that are inherently detrimental to the US, and so this part of the deal is essentially null and void. Annoying Orange's plan means nothing if competent politicians won't agree to it.