The Slicery is a pizza parlor where Sabrina and her friends hangout in Seasons 1-3.
The only employee that Sabrina and her friends seemed to interact with was Mrs. Popowski, a very sarcastic waitress, who always mispronounced Sabrina's name as "Saleenus." Mrs. Popowski was also Sabrina's first on-screen boss, during her very brief employment.
The Slicery's first apperance is in the season 1 episode "Bundt Friday" and its final appearance is in the Season 3 episode "Sabrina and the Beast."
Starting with Season 4, Sabrina started hanging out at the Bean There, Brewed That coffee house, instead of The Slicery. It is implied that Harvey continues to hang out here, though, in Season 4.
The customer side of The Slicery.
Sabrina and Valerie working at The Slicery.