I was going to suggest checking out the reviews also. Some of those off site places have just horrible reviews. All of the ones located in the main building are normally okay. I have even heard that some of the off site places MAKE you take the added insurance which normally doubles the cost per day. Rental cars in Vegas used to be really cheap but lately they have become very pricey. I used to get a weeks rent for under $100 (plus added fees). Now days you are lucky to get a week for under $200 and of course the fees are also double. I use Travelocity as they always seem to have the lowest rates and biggest choices. Also if you pay when picking up the car you can rebook it when prices drop and they normally do have sales. Saving a few bucks by prepaying normally is not worth it.