Tipping is an important part of the economy in Las Vegas.
Some tipping guidelines:
Casinos -- If you get lucky while playing the Slot Machines or Video Poker machines, it is a good idea to tip the people who hand you the money. Give a couple of bucks to the change person (especially if he or she pointed you to the winning machine) and to the change cashier. For dealers at Table Games, the custom is a little different. Either tip them a few bucks as you leave the table, or place a bet for them when you are winning. It is also nice to tip Keno runners a few bucks if you are playing for a long time. When you cash in a ticket at one of the Race and Sports Books in town, drop a few singles in the ticket writer's hands, especially if he or she was helpful with information when placing your bet. In general, drinks are free at most casinos if you are gambling, but be sure to tip your server. Servers usually get $1-$2 per drink. For a round of drinks (for four people or more), add a few more.
Hotels -- Bellmen and doormen customarily receive $1-$2 for each bag they handle. Hotel maids and housekeepers traditionally get $1-$2 for each day at the end of your visit (leave on the nightstand). Pool attendants should get $1-$2 for bringing you towels or finding you a lounge chair. Room service attendants appreciate the standard 15-20% of the tab (look at the bill first, as it may already be added). Washroom attendants also appreciate 50 cents to $1 for their service. You may also get special perks by tipping the front desk clerk at the hotel.
Restaurants/Buffets -- Waiters and waitresses expect the standard 15-20% tip for good service. Buffet servers usually receive $1-2 per head when they get your drinks. For groups of 8 or more, an 18% gratuity is normally automatically added to the check (Eviejd 12/5/2010).
Transportation -- Taxi drivers are given $1-$2 for a fare below $10. If the total is higher, and the driver is friendly and helps with your luggage, a 15-20% tip is proper. Limo drivers should be tipped 15-20% for their service. It is also nice to tip your tour bus or shuttle driver at the end of a trip. For valet parking attendants, $2-$3 is appropriate. And don't forget to give skycaps $1-$2 per bag.