I'd like to provide a flip side to that advice. Tier 1 runes are incredibly good value (relatively). I believe theyre a bit more than half the strength of tier 3 for a tenth of the cost. You could always buy "general runes" that work for almost any hero (that's what I did!) which allows you to play almost any champion effectively.
I can't find the rune guide but here's my general runes:
Red: Mpen, ArPen
Yellow: Mana Regen, Armor
Blue: CDR, Magic Resist per level
Quits: HP, Movement speed
I can't find the rune guide but here's my general runes:
Red: Mpen, ArPen
Yellow: Mana Regen, Armor
Blue: CDR, Magic Resist per level
Quits: HP, Movement speed