In January of this year, the 9th U.S. Circuit Court of Appeals ruled that the California law that banned credit card surcharges was unconstitutional because it violated businesses' free speech rights  (Italian Colors Rest. v. Becerra). This decision affirmed a previous (2015) federal district court decision in California. 

And, a recent (2017) decision of the U.S. Supreme Court likely opened the door for surcharge laws to be universally deemed to violate the First Amendment (Expressions Hair Design v. Schneiderman).  

Please note: Per state law in New York, Maine and Kansas schools cannot pass along credit card fees to families legally. Criminal penalties & fines can be assessed to schools for doing so.