Try this...
insert into #T
select * from
(
SELECT acf.ID , acf.ID2 , acf.CNK , acf.Omsch , acf.Groep , acf.prijs
FROM dbo.Acf_LstPrijzen acf
WHERE HstDate = '2013-12-01'
INTERSECT
SELECT acf.ID , acf.ID2 , acf.CNK , acf.Omsch , acf.Groep , acf.Prijs
FROM dbo.Acf_LstPrijzen acf
WHERE HstDate = (SELECT MAX(acf2.hstDate)
FROM dbo.Acf_LstPrijzen acf2
WHERE acf2.HstDate < '2013-12-01'
AND acf.id = acf2.id
GROUP BY id)
)