LORELAI: Are we allowed to be hearing this [lecture]?
RORY: I don’t know.
LORELAI: They wouldn’t charge you a hundred bucks or something just for listening to part of a class?
RORY: I don’t think Harvard would nickel and dime people like that.
To “nickel and dime” is an Americanism meaning to fleece a customer by charging small amounts of money for various extra services which greatly increase the overall price. Rory is presumably being ironic by saying that a hundred dollar charge would be “nickel and dime” stuff.