SQL Server 2012

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CREATE TABLE YourSampleData
(
  Id INT IDENTITY(1,1) PRIMARY KEY,
  ExpenseType VARCHAR(30) NOT NULL,
  Price INT NOT NULL DEFAULT 0
);
INSERT INTO YourSampleData 
(ExpenseType, Price) VALUES
 ('Car', 100)
,('Hotel', 50)
,('Gold', 1)
;
3 rows affected

SELECT Id, ExpenseType
, COALESCE(a.Price, t.Price) AS Price
FROM YourSampleData t
OUTER APPLY
(
  SELECT Price * Perc AS Price
  FROM (VALUES 
    ('Car',0.3E0), ('Car',0.7E0)
   ,('Gold',1.618E0)
  ) AS v(ExpType, Perc)
  WHERE t.ExpenseType = v.ExpType
) a


Id
ExpenseType
Price


1
Car
30

1
Car
70

2
Hotel
50

3
Gold
1.618