I have a walk out attic over my garage. I was able to install myself r13 batts of over the 3rd car garage area as the studs fit the insulation perfect for what I installed in the walls of the garage. I had extra so used it up. The only section left to insulate is the 2 car part, but am not sure if it is worth it. I got a quote for $320 for blown in insulation that is 460 sq ft worth for the size. That is for R30 with 12" of blown in. The 2nd car side has 12 or 14" deep joices so a lot more can go in than the 3rd car side. The studs are 24" inches apart in the 2 car part so I think it would be more economical to have it blown in that go by batts at HD/Lowes.

Ok... the question.. Is it worth it to do this? Will I save money in the long run for the house or simply have a better insulated garage and attic. I plan to floor the attic, but would need to take care of this before doing that. Thoughts and suggestions.

Oh yeah.. I live in Oklahoma... to give you an idea of the climate where the house is

You have said quite a bit here, which is hard to follow, but the short answer is, that insulating as much as is practical is always worth it. It is cheap compared to gas, or electricity and will look like a no brainer in a few years.

If your garage below is unheated you won't save much by adding insulation to its attic. HOWEVER, you should insulate the wall between the garage and the heated part of the house if this has not been done. I just recntly did exactly this by adding 2" foam board to that wall. I also extended the wall all the way to the ceiling of the garage attic and then added 6 inch insulation over the area that is heated below (mudroom between garage and house.