Some tour companies offer a wide variety of services to their customers. For example, when you book a Las Vegas Grand Canyon tour with some companies, they offer the opportunity to book Vegas shows, Grand Canyon hotels, and other tours, along with your Grand Canyon tour.
Most companies will also create custom tour packages just for your family and friends. Many offer vans driving from Las Vegas to Grand Canyon, instead of large tour busses, so you can have a more intimate experience.
Make sure there are no hidden costs in your Las Vegas Grand Canyon tour. Some tour companies advertise low prices, but do not cover "extras" such as your entrance fees to the park.