From this Gadsden Times article:

A new federal lawsuit was filed Friday challenging a section of Alabama’s immigration law that civil rights groups say makes it impossible for those who can’t prove U.S. citizenship or lawful immigration status to legally keep their manufactured homes.

They are challenging a section of the law that prohibits most contracts where one party is an illegal immigrant.

Attorneys for the plaintiffs say that provision is being used by state revenue officials to keep illegal immigrants from paying an annual registration fee and obtaining a decal that by law must be displayed on manufactured homes. State law requires the registration to be renewed by Nov. 30.

This part of the law, like so many others, is a blatant violation of individual rights.  Is America not "the land of the free"?  Free men should be allowed to trade amongst and enter into contracts with each other, so long as they are not violating the rights of anyone else.  Neither these immigrants nor the manufactured home seller is violating anyone's rights by buying and selling the home, and their business should not be interfered with by anyone, much less the very government that is entrusted to protect their right to do business with each other!