While it may be possible to put into service a testing program from existing resources for a reasonable amount of money, what does increase the funding level are the resources in both materials and personnel to carry out the remediation programs necessary to bring nonproficient students to proficient status.
I taught in the public school system in Florida while their program was administered. Such programs are easy to conduct when there are relatively few students identified as nonproficient.
This is typical of how people and the government make a mountain out of a mole hill. As that has to be done is that if the student fails the curriculum for the grade, they fail and have to repeat the grade. If you do that the first time they fail, they will be able to learn the curriculum as they repeat it. You really don't need any special testing or additional programs.
As things are now, the student is promoted until he/she doesn't have any hope of catching up and eventually they drop our. That is why we have such a high drop out rate. If we would demand that students learn the curriculum before they are promoted, they would try harder because they do not want the embarrassment of failing.
When I was in school, one of my friends failed the third grade 3 times. Once he learned to read, he was promoted up and he went on to become mayor of his city.
We must graduate educated students. We cannot continue to graduate students who cannot read, write, or do math.