Float is a very bad choice for monetary values as it's approximate numeric.
I would recommend Decimal which is precise (exact numeric).
You can use Money too, if you brave enough, but be aware of how it behaves in calculations:
declare @m money
declare @d decimal(10,4)
select @m = 19.34, @d = 19.34
select (@m / 1000)*1000 as [using money], (@d / 1000)*1000 as [using decimal]
Ops... :w00t: