Forget everything you remember from 20 years ago; D&D basically reworked everything from back then lol. Now everybody from druids to clerics can cast weak spells (cantrips) endlessly, and the main thing about sorcerers is they can use "metamagic" to upgrade their spells slightly and they can cast any spell they know with their spell slots. they dont prepare spells into specific slots. However they do still only know a very small amount of spells relative to most classes.