Las Vegas is great year round! From June to August it is definitely hot! So make sure to pack tons of sunscreen and a hat. During the winter months the temperature drops significantly. Packing a jacket is highly suggested during the winter.
For the cheapest hotel rates plan to travel during the hot summer months. Be sure to book a hotel with a great pool! Try to avoid traveling during major events and conventions for even lower rate fluctuations.
It is best to rent a car to get around Vegas. Casinos offer free valet parking but make sure you tip! There is also a Monorail that runs from the MGM Grand Hotel to the SLS Vegas and has several stops between. Ride sharing is also available!