So, you can't edit rune pages while in champ select apparently. I got a few questions. Should I buy more rune pages and make each for every role (AP mid, top, adc, supp and jg), or do they vary even within the role? It seems unrealistic to try to make a rune page for every champion and every play style. Also, can one rune be used in different rune pages?
They vary within the role on two of them, support (Alistar and Soraka are examples of the types) and jungle (Sejuani and Lee Sin). Otherwise, one page should be good enough for meta champions.
You don't have to buy rune pages for every role, especially if you don't play them all. Some people do fine with just 2 pages - one for AD (top/adc/jungle), one for AP (mid/support). They both have armor seals and magic resist glyphs; only the marks and quintessences change.
If you're only level 21, you don't need to worry about getting more than that yet. You can fill out your rune pages after you've been playing longer and to suit your own style and preferences. (Hint - rune pages go on sale 1 or 2 times a year.)
Yes, you can use the same runes on multiple pages.
