I have to agree that JUCO is probably your best route, especially if money is the issue. What a lot of people seem to forget on this site is that most D3 schools HAVE WAY TOO MANY COMMITMENTS! They are bringing in paying students for the D3, not student-athletes! You could bite the bullet and pay the $$ at the D3 schools he loves (and hopefully he loves it because of the education and not the baseball program) and then find out that the baseball program is grossly over-committed (high probability) and/or perhaps baseball is not in his future. If the education is good and you are OK with the $$ then fine. Otherwise you have wasted your $$.
If he goes JUCO he could still find out baseball is not in the cards but at least it won't have had the same price tag. And he can still transfer to the same D3 (for the education) or a different 4-year school and you will have saved a ton of $$. Or he may thrive baseball-wise and be looking to transfer to another school for baseball in a year or two. Perhaps he may even be offered an athletic scholarship!