Try this:
SELECT EmpID, CashID, CashName, SUM(Incentives) AS SumOfIncentives
FROM YourTableName
GROUP BY EmpID, CashID, CashName
Example for total SUM:
DECLARE @tmp TABLE (A INT, B INT, C VARCHAR(10), D INT)
INSERT INTO @tmp (A, B, C, D)
SELECT 1 AS A, 2 AS B, 'A' AS C, 2 AS D
UNION ALL
SELECT 1 AS A, 2 AS B, 'A' AS C, 3 AS D
UNION ALL
SELECT 2 AS A, 3 AS B, 'B' AS C, 4 AS D
UNION ALL
SELECT 2 AS A, 3 AS B, 'B' AS C, 5 AS D
SELECT A, B, C, SUM(D) AS SumOfD
FROM @tmp
GROUP BY A,B,C
UNION ALL
SELECT 0 AS A, 0 AS B, 'Total: ' AS C, SUM(D) AS SumOfD
FROM @tmp