SELECT * 

FROM 

(

     SELECT *,  

                 (SELECT SUM(price) 

                  FROM test AS x 

                  WHERE x.IDArt <= test.IDArt 

                             and x.price - x.paid > 0

                 ) AS SumMeAndPrev

    FROM test

    WHERE price - paid > 0

) AS T

WHERE T.SumMeAndPrev < @suma