There is no charge for valet at any of the strip hotels. it is completely free, just leave your car, get a ticket, return with the ticket and when your car comes up give the driver a couple of bucks. You can leave the car with them all week if you want, still no charge.

BTW I would price up a car separately using one of the comparison sites, you will probably find that the car including insurances will be cheaper than the car you got with the deal. You will be required to buy all of the insurances and taxes additionally when you get to Vegas with the included car, and that would be a pretty penny. I am at the moment renting for 9 days fully inclusive of all taxes, insurance and fees for £160.00.

I can almost guarantee you that the fees you will have to pay at the car rental lot will be more than that. You are under no obligation to use the car that you get with the flight.