A casino comp is actually a bonus, freebie or complimentary credit that a casino give to its players and comps are very popular in the gambling town of Las Vegas. These comps are given on a rating system like when you sit at a gaming table and the dealer takes you name and tracks or rates your play.
It is the choice of the pit boss, supervisors or managers to sign for complimentary meals, rooms limos and even airfare if you are rated as a high roller. Comps will vary as to how busy the casino is so what you might get during the week will be different from what is given on a busy weekend.
Casinos like those who spend many hours playing so a person who bets, for example, ten or twenty dollars per hand for several hours will rate for better comps than that person who throws a one or two thousand bet on a table as he walks by.
Casinos want you to feel special so you will return to their business. Slot players can qualify too for comps as they become a member and insert their card in each machine they play.