DUDE!
You don't get it, makes me seriously question your business "acumen". (And try to stay focused here.) You used an imaginary example of an increase in the price of goods from Mexico being used to pay for that wall. But I can't think of a single thing from Mexico that I need. If the price of something like avocados goes up I stop buying them. I may miss having them until the world-wide supply chain adjusts to that shift, but I won't die. Your position sounds more like a drug addict that's about to be deprived of their next "fix".
And speaking of that drug addict angle I think that Pablo Escobar is alleged to have over 16-billion dollars stashed in the US. Seizing that would make a heck of a dent in building that wall without putting one dime of taxes on the citizenry. So that's another very good option for paying for the wall. (Yes, I know, the cost is estimated at around 2-billion. But it's going to be a "government" project and we all know that if you put the Federal government in charge of the Sahara desert they would run out of sand in less than a year.)
But even if we do pay for the wall as you seem to think that price will be a LOT less than what we've already paid for NOT having the wall and actually enforcing our immigration laws. It might actually help stem the loss of jobs to off-shore locals and ease the burden on hospital emergency rooms which would really help to make healthcare more affordable.