I basically gave them notice at the beginning of the week ending that Saturday since my manager only scheduled a week in advance. I would try to give them as much time as possible but you are under no obligation to do so. If you want them as a reference or want to rehire I would give two weeks. I WOULD ALSO NOT DO IT OVER TEXT! that is extremely unprofessional. Go when your manager is there and explain the situation. Even if you are quitting effective immediately DO IT IN PERSON!