I know spending the money ain't easy.
But just how cheap do you want to go on the components that STOP the bus?!?
If you do it right to start with you'll thank yourself every time you mash the brake pedal. So far as I can figure you're talking about $450 or so for parts; if you could cut that in half (and you know that's not probable) you only save $225. I'm not sure it's worth it if you can get the parts locally and not have to spend hours on the phone and/or the Internet looking around then fussin' with shipping. And, especially not if by throwing some business to the local folks you get more help (advice) in the future. For instance; would you have known what part numbers to go looking for (or even if there was a reman booster available but not a master cylinder) if the person at the local shop hadn't taken the time to look it up for you? What if you had bought the wheel cylinders over the Internet and found out they were the wrong ones? Sure wouldn't have been just a trip back to the local place for a swap.
Just my $.02 worth...