Id gladly donate money to build the wall..I know many others who feel the same way. I think I read a while back that if everyone who wanted to donated a 125 bucks each for the wall it could be built
The procedure for financing public works is to sell bonds. You and others would buy such bonds.
There is a fantastic pool f tens of billions of $$ of the repatriated corporate money.
That money must be invested. Wall bonds are a great and safe place to invest it.