Hi,
I remember I read something about some spell that cost huge amount of mana that you need to cast for the mage guild quest line and you might find out not having enough mana. I'm a thief/assassin but would like to do that quest line too with the same character maybe after finishing the main story line.
So, is that true and how much mana would you need for it (with no cost reduction perks)? Also how much additional mana/cost reduction could you get at most from enchanted items (no perks)?
And, in the end, what's the most mana consuming spell, even if what I stated in first paragraph is not true, and how much is that (again no cost reduction perks)?
Thanks

I just joined the mages guild at level 30-something with my warrior. I haven't increased my magicka at all. The woman at the bridge asking me to cast Firebolt, which I was able to do with both hands (just for fun).

*edit* You did mean the very beginning, right?

I dont remmeber anything like that, only moment you need mana is when you have to cast a ward spell, honestly 100 may just be enough.

I believe it was reading about the beginning of mage guild quest line but may be wrong. But I would be interested about the whole the quest line, in fact if lacking mana can prevent any quest from game not only in mage guild.

I had to cast Fear on the ground to get in. My character didn't have enough base magicka to do it, so I found some armor that increased my magicka and then drank a potion that did the same. I was able to cast it and get in. It wasn't an issue after that.

it varies what she tells you to cast based on your conversation choices.
If you go the right (wrong?) direction, she will ask you to conjure a flame atronach, and if you havent done any conjuration or perks, or a scroll, or a +mana item, you might not be able to cast it.
If you cant find a way to cast it, you dont deserve to be a mage

That said, just steer the conversation away from conjuration, or trump it entirely by saying you are a dragonborn.

Actually all you have to do is shout anything at her and she will let you in. Problem solved.

Save before speaking with Faralda.
The requested spell to cast is completely random, but it will be one of these...
1. Firebolt
2. Summon Flame Atronach
3. Fear
4. Healing Hands
5. Magelight
If you have the Magicka but not the spell, she'll sell it to you. Just reload the Save until the requested spell is doable.

There's also a way to do a shout to get in and you can cast from a scroll.

With a really really good choice, you don't even have to cast a thing.
I was able to pass by telling them i'm dragonborn lulz

Or you can just say you are dovakin, and proceed to do a shout.

just dont Fus Ro Dah the npc asking

True.
As for shouts, some don't wish to start the MQ and have dragons spawning like lemmings.

Their spawn rate seems tied to MQ progression. If you just get them started, they're still rather rare.

I told her I was Dragonbone and used an Ethereal Shout. She was impressed.

The spell she ask you to cast, depends on what you answer her when she ask you why you want to join the college.

Damn. I was just getting excited too!

I told her I was Glass and she stole my sweet roll.

If you grab any mage gear (e.g. off the body in a cage where the executioners are duringthe escape from Helgen), and maybe use a perk or two you should be able to get into the College as fast as you can get there.
Bandits and wolves etc on the road up to Winterhold should give you experience enough for a level or two to gain any extra Magica and perks if needed.