Q/Q Team/POTUS,

Whomever is consulting you on the cost of building the wall is scamming you on the order of '$700 toilets' that happens in the military (for black budget purposes).

Here is the info on how much it costs, for example, to build a mile of road (a much more expensive and complicated engineering feat):

[sauce: https://medium.com/@TimSylvester/i-agree-it-sounds-astronomical-but-i-actually-understated-the-costs-according-to-artba-2e8baeac2a46

also: https://www.artba.org/about/faq/]

(in the section: How much does it cost to build a mile of road):

There is no single answer to this question. Construction costs per mile of road depend on location, terrain, type of construction, number of lanes, lane width, durability, number of bridges, etc. It costs more to build a new road than to rehabilitate a road or add lanes. Roads cost more to build in urban areas than in rural areas. Roads in mountainous terrain are more expensive to build than roads on flat land.

Nonetheless, some states have developed cost models to guide planning for their highway construction programs. These models give a ballpark figure for various kinds of highway improvements. The following are some examples:

Construct a new 2-lane undivided road – about $2 million to $3 million per mile in rural areas, about $3 million to $5 million in urban areas.

Construct a new 4-lane highway — $4 million to $6 million per mile in rural and suburban areas, $8 million to $10 million per mile in urban areas.

Construct a new 6-lane Interstate highway – about $7 million per mile in rural areas, $11 million or more per mile in urban areas.

Mill and resurface a 4-lane road – about $1.25 million per mile.

Expand an Interstate Highway from four lanes to six lanes – about $4 million per mile.

The Florida Department of Transportation has published its generic cost per mile information online. The Arkansas Highway Department’s estimated cost per mile for 2013 is available online.