skyrim: spell tomes

hey i am buying some spells from a wizard: just after the quest "dragon rising" , so i buy what i think are spells, but they are called spell tomes, i don't know why they are called that instead of just spells, so anyway, i buy until i run out of gold,then after i leave my inventory says that i haven't bought any spell tomes at all and it takes up a lot gold too. help please thanks

Go to your inventory, then books, and then read the spell tomes, which adds the spells to your list, which you can just equip to use. :)