I have one month to prepare for the SAT Math 2 subject test from scratch, and I need to write a 750+. I am able to put in 6+ hours a day if that is helpful information.
How are your grades in math courses?
Preparation is great, but will not be as important as 12 years of studying math in school.
Can you afford a tutor?
Nobody, I mean NOBODY should put in 6 hours a day for a month for a subject test. If it takes you that much to get a 750, I hope you are not going into a STEM field. Maybe an hour a day, although if you have a strong math foundation, even that is not necessary.
Where would you find 6 hrs a day to study for one test?
I hope OP means 6hrs a week.
Well, I thought that the more time I could put in the better my results would be. I am finding time in the evening to do this much time, but that was why I was asking for a good ways to go to work - at this stage I am just trying to cover all of high school math to make sure I understand everything perfectly and I figured that would be the amount of time taken for that strategy. Thank you for your response 
I have all A’s through 8th until AP Calc now, although trigonometry seems to be where I am making some errors. I did find a tutor to put approximately 7 hours of time in with. Thank you for your response!
“I did find a tutor to put approximately 7 hours of time in with”
7 hours of tutoring in total (not per week) should help quite a bit. If you are already strong in math, then I expect that you will do well.
Have you already tried a practice test? This should give you a good sense of how well you are already set to do.
Thank you, that’s what I thought! I just never want to be unprepared and then hurt my chances because of it. I appreciate your help.
Have your tried the practice tests, or the tests in the Barron’s prep book, which are harder than the typical test?
I find that Math isn’t something you effectively can cram for - I’ve you’ve studied and done well at accelerated/advanced math over the years, you should be in good shape. If not, it’s not a subject where you can short-term memorize facts and dates.
After pre-calc/Trig is the best time to take it, as that’s the most advanced math on the test. So don’t bother studying Calc. If you’re in Calc now, the trig identities are probably the most likely to be forgotten. Study them, along with the graphs/phases of the basic functions.
Barron’s was the best book for my D to study/refresh.
Especially for math, I think practising with physical copies of tests/books is far superior to doing it online. This might be helpful: get copies of the practice tests; find a quiet room in the library or school (but not in the comfort of your home or a cafe); set a timer; do the tests without interruption. That is, practice under simulated test conditions. Our brains do adapt very quickly (even in a few days); you can do it, good luck. Go over the questions missed and figure out why. One or two sets of tests a week should be enough. Be assured that you have accumulated already years of knowledge on math; you just need some refreshment.