[Out of country but legal.]
Anyone out of state has to move to Texas and live here one year before getting the ‘instate’ tuition.
A foreign national who has lived in Texas for three years, who graduates from a Texas high school or gets a GED, and who signs an affidavit promising to seek permanent-legal-resident status in the United States if they become eligible for that status, is given in-state tuition at Texas public schools. This applies to foreign nationals who have entered the U.S. legally and illegally.
Instate tuition is what all Texas kids have to pay.
That simply isn't true. There is no such affidavit requirement. The law itself makes no mention of immigrantion status. 3 year residency is all that is required in addition to a high school degree or GED. You could be a 25 year old illegal with a GED and get in-state tuition.
Read the current legal challenge to the Texas law, Immigration Reform Coalition of Texas v. State of Texas (University of Houston),
This is meaningless. "eligible to do so" is so ambiguous to be unenforceable.