My $29 Vegas ticket shows the carrier interface charge, so at the airport this fare would be $19.98
US1 - U.S. Transportation Tax
$0.39
CIC - Carrier Interface Charge (Non-Refundable)
$10.00
AY1 - U.S. Passenger Security Fee
$5.60
ZP - U.S. Domestic Flight Segment Tax
$4.30
XF - Minneapolis/St. Paul, Mn (MSP) Passenger Facility Charge
$4.50
TOTAL PAYMENT DUE
$29.98