(
@Amount DECIMAL(18,2),
@Freight DECIMAL(18,2),
@FreightName VARCHAR(500)

)
AS
SELECT FreightName,

CASE WHEN (FreightName= @FreightName) And (UseFreight = 'TRUE') THEN
'$' + Convert(varchar(25), @freight,1
ElSE
'$' + Convert(varchar(25), 0.00,1
END AS Freight
FROM
tblFreightType
WHERE FreightName=@FreightName

when i execute the query it says cant convert varchar to numeric