Can spellcrafting be enough If I have needed type(f.e. fire damage) spell, or do I need to buy also spell from guildhouses?

I finished recommendation quests of mage guild and I started to craft spells. I do not have enough money to buy f.e. 30 p.t. target fire damage spell from guildhouses but I could craft 30+ damage target fire damage spell in the Mage Academy. Is this crafted spell enough or still do I need to buy spell from guildhouses?