We taxi back most of the time from MSS at about midnight. The fare is just over 30 dollars and there is hardly any traffic. The driver uses the Freeway and then exit on Tropicana. It costs about 5 dollars extra tunneling. Coming from the airport, you have to add that airport pick up fee.
There was only one time the driver used Main Street, crossed over to Paradise by the Stratosphere. The fare was just over 25 dollars.