Thank you very much, ditzy.
If it is on the upper limit, the cost of having 5000 CDs is $0.40 x
5000 = $2000. So I need to know how much do they actually charge.
You see, their production cost is not my production cost, because
my production cost is their selling price (their production cost +
profit). 
Do you know what's the minimum quantity that they can accept before
they can do mass production?