Season 2: Episode 27: 1-900-CRUSHED
Zack's money making schemes never seem to fail, well, they start off well. This time isn't much different. Zack starts a "Teen Line" (or "the Lisa Line") where Lisa gives advice to callers. When Zack refuses to pay, Lisa quits, and Zack is forced to run the line by himself. Kelly's sister Nicki has a crush on Zack and calls the Teen Line for advice, but Zack gives her the wrong advice and he ends up having to deal with the consequences.