Spell Checkers Volume 1

Three teenaged witches use their power for popularity, good grades, and the
good life. When nasty graffiti starts showing up about them at their school,
they first suspect one another. But when they start losing their powers, and
their magical fetishes disappear, they realize this is an attack from outside
their circle, and they must join hands (and wits) to defeat the usurper and her
demon companion!