The figured being suggested for border wall funding are large.

Corruption has been found in some of the past border wall building efforts.

New allegations in border fence lawsuit: racketeering, bribes and money laundering

Recent court filings in a case brought by Hidalgo County against a former employee who oversaw construction of a Bush-era border barrier allege a vast kickback scheme worked out over drinks and steak dinners.

The Texas Tribune

Some have gone so far as to question whether Trump or Trump cronys might personally profit.

Could Trump's "big, beautiful wall" be a profit engine — for him?

Trump's entire career has been mired in corruption. Why should his ludicrous border wall be any different?

Salon

Certainly an area to keep an eye out, even among some of the recent companies involved with border wall prototypes.

Bad Actors Among Border Wall Contractors

Half of the six contractors that built border wall prototypes had questionable track records, including one contractor that the Army Corps of Engineers felt was too risky to do future business with.

Project On Government Oversight