I'm unsure if this is what it says in the raw japanese, but I'm guessing she says the word "service" in english, and like the word "style" (meaning body/figure) or "pudding" (flan custard), among many other english words used in japanese, meaning isn't direct english equivalent. Its as others said -free food/extras. Though whether or not it gets translated quite literally or left alone, scanlators decision and then its for readers to understand the meaning. (Style/sutairu took me a while to understand until translations actually did start changing it to mean body/figure, and previous scenes made more sense.)