[Radek]

Yes but don't expect any super spellbooks for a long time. More precisely, you will find spellboks starting from Serpent Temple but you will have to wait for level 7 spellbooks until you reach Brimloch Roon.
Therefore, you'd better buy high level spellbooks in the guilds and get high level spells during promotions. Don't wait for the spellbooks in chests.
As it has been said, always learn the highest level spells possible during your promotion. Once you get all level 7 spells, you can get all other spells in any role but you will need skill level 12 in all magic schools for it. You can train in guilds. If you add all level 6 spells then you will need skill level 10 for all remaining spells so that you will save money.
At any rate, money should not be a problem later in the game. Once you get Fletchery, you can duplicate enchanted dragon arrow. If you aren't patched then you can generate money in the inn. In the other words, you should have enough money for training your magic schools to 12.
Therefore, get all level 7 spells and you can change role.