If you clicked on the link, I find they are for Round Trip (R/T)
To/from Las Vegas (R/T fares):

New York (JFK) $198.00
Boston (BOS) $228.00
Tampa (TPA) $168.00
Orlando (MCO) $168.00
New Orleans (MSY) $148.00
Portland OR (PDX) $ 98.00
Tulsa OK (TUL) $ 138.00