Thanks for the post but (and keep in mind that I'm a newbie here) how do you get to purchase those killer spells in the first place? You need like 700+ magicka for some of them. Previous posts explain that raising your luck and levels with the applicable spell school is the way to go. Do you have any other advise?
The amount of magicka is not 700+ and it's pretty much irrelevant, as I said, because you include the magicka cost in the spell itself as a temporary pool. For example, if a spell effect you want costs 50 magicka, Fortify Magicka is sufficient to continuously cast the spell (Fortify Magicka +100, 3 secs and spell effect). Fortify Magicka +100, 3 secs boosts your magicka by 100 for 3 secs, so casting a 50 point spell costs half the temporary boost and leaves 50 left over... which is enough to cast the spell again, leaving 50 left over... etc, ad nauseum. Same for higher cost spells up to 150 points but using a combination of Fortify Magicka and Fortify Intelligence (the calculation is a bit more involved, but not much, and the principle remains the same, of course).
Check the Hints forum and search for "spell chain." I posted very extensive explanations of how to build such spells last summer. Some of those posts might also be in this forum, but I know I had extensive discussions in the Hints forum (mostly helping some new players such as yourself).
If you want to know specifically where to buy or acquire certain spells or effects, you can check the UESP wiki.
As was mentioned in this thread by others, increasing magic school skill level decreases the cost of the spells in that school.
In addition, increasing Willpower increases magicka regen rate. High Willpower can make low cost spells continuously castable even without temporary magicka boosts.