Conditionally replacing values in SELECT

SELECT     totalhours * staffbaserate AS TotalCost
FROM         newrotaRaw
WHERE     staffref = @staffref

SELECT     TotalCost =
    CASE
    	WHEN (totalhours * staffbaserate) < 105 THEN (totalhours * staffbaserate)
    	ELSE (totalhours * staffbaserate) * 1.128
    END
FROM         newrotaRaw
WHERE     staffref = @staffref

SELECT
    CASE WHEN totalhours * staffbaserate <= 105 THEN totalhours * staffbaserate
         ELSE totalhours * staffbaserate * 1.128 END AS TotalCost
FROM         newrotaRaw
WHERE     staffref = @staffref

SELECT    totalhours * staffbaserate * (CASE WHEN (totalhours * staffbaserate) < 105 THEN 1 ELSE 1.128 END) AS TotalCost
FROM         newrotaRaw
WHERE     staffref = @staffref