WALL Act of 2018 This bill appropriates $25 billion for the construction of a wall on the U.S.-Mexico border. The amount shall remain available until expended. As offsets to the spending, this bill amends the Internal Revenue Code of 1986 to restrict the child tax credit, earned income credits, and lifetime learning credits to those with social security numbers and not prohibited from employment in the United States. Also, individuals who file taxes using an individual taxpayer identification number instead of a social security number shall pay a $300 fee. This bill also sets fines for aliens who improperly enter the United States or overstay their visas.