🚀 go-pugleaf

I am interested in preparing long, technical documents
on a Mac.  I need to typeset complicated mathematical
expressions, and create diagrams (similar to flowcharts)
and graphs, and merge them all together.

I am somewhat familiar with TeX, and like it a lot.
But I have only used it for typesetting words and equations,
(on a PC!) and have not tried merging graphs and diagrams.

Here are my questions:

(1) How much memory does MacTeX need?  
    (I've read in this newsgroup that 1 Mbyte is just
    barely enough for TeXtures or LaTeX.  How about
    the latest version of TeX?)
    Is MacTeX sold somewhere at a student price?

(2) What's a good graph-making program that creates output
    that can be merged with TeX?  
    (I've read in this newsgroup that Igor is great.
    Is its output TeX-able?)

(3) What's a good diagram-making program that is TeX-able?

While you're at it, maybe you could educate me about the basics
or PostScript-ing.  Is PostScript a separate program or part of
TeX or what?  

Thanks!  --John Kruschke (soon to be a Mac owner)