The title of this episode is "Santa's Little Helpers". Episode 10 in Season 1 was named "Santa's Little Helper.
At the end of the episode, Mr. Feeny reads "A Christmas Carol", he also reads the story in the Season 5 episode "A Very Topanga Christmas" and in the Season 1 episode "Santa's Little Helper".
Shawn: I hate being the third wheel.
Cory: Oh, please. You know, you've been the third wheel with me and Topanga so long, I think of us as a tricycle.
(Eric recruits Jack to be a mall elf)
Eric (jovial): You're going to be making like five bucks an hour!
Jack: Wait a second, you get twelve bucks an hour?!
Eric: Hi--I'm Santa. You're just an elf. Read your bible.
Amy: Eric, its Christmas Eve. I thought we were gonna spend it together
Eric: I'm Santa!
Eric: Elfboy, here's Santa's dad's credit card.