Original: Cheap pop when a wrestler (often a face) incites a positive crowd reaction by "kissing up" to the crowd (for example, mentioning the name of the city or complimenting a local sports team).
Simplified: Cheap heat when a wrestler (often a heel) incites a negative crowd reaction by insulting the crowd (by insulting the city or a local sports team) or by using a news event as part of his promo.