If you put skill points into your Lore skill, you will be given Lore Points to spend on spells. Your first rank in the skill will give you four points, the next gives 5, then 7, then 9, then 10 for every rank after that. (For Lore 5 or up, the total is 35 + 10 per rank above 5.)
You cannot learn spells unless you have enough Lore Points. Every spell has a Lore Cost, which is how many Lore Points you must spend in order to learn the spell.
The base mana cost for a spell is 10 times the Lore cost.
New Verden - Magic Shop
Minath Elion - Training Hall
Fae Wyston - Mage Guild