Check out the CAT bus from the airport to downtown. Take bus #108 or #109 north for only $1.25 or $2.50 for an all day pass on CAT buses not including the Deuce, which runs on the 'Strip.' If you are staying at the Hilton, Riviera, Sahara, or Stratosphere, use the #108.
Catch the bus from the airport on the zero level, which is downstairs.
Catch the bus from the airport on the zero level, which is downstairs.