From the link:
“If the 63 million people who voted for Trump each pledge $80, we can build the wall.”
That equates to roughly 5Billion Dollars, even if we get half, that's half the wall. We can do this.
From Business Insider:
In January,
Trump wanted $25 billion for his wall, but Congress shot him down and provided just $1.6 billion.
An internal report that Reuters obtained in February 2017 said the wall would cost as much as
$21.6 billion. Other estimates have placed the costs higher, with Democrats asserting it could reach
$70 billion to build.