The plan is to pay for education with a small tax on stock market trades. This would probably mean that there would be fewer minute traders, but that should nopt upset things too much. I might well have the effect of making the market less skittish, and that is a good thing.
Since no president has more than a fraction of the power to impose a complete platform, what he proposes is, like every other candidate, problematical.
It is clear that a post secondary education in 2016 is as necessary as a high school education in the 1960's.
For a rise in employment year after year, it is clear that a small amount of inflation is absolutely necessary. This serves as a cushion against violent swings in the economy, which were common until FDR's reforms in the 1930's This also means that the poor will be 2 or 3% less well off each year, because of this inflation. It is one of the reason the poor get poorer.
If Trump actually believes the patent bullshit that he spews about the economy (that most jobs have been stolen by Mexico and China, and that trade agreements have all been a disaster) , then he will have a horrible forth two learen learning that his basic beliefs are just nonsense. He might them be smarter to actually understand what is needed.
Bernie and Hilary both understand economics better than Trump and Cruz. I don't know enough about Kasich to judge what he might do.