Using Multiple Choices to Select a Value in a Cell
 

I have developed a worksheet which is used to calculate a cost dependent on a
number of variables. The worksheet is used by other people; to ensure that
only valid entries are made, I use drop down boxes to guide the user entry.
It is very important that the entries be correct for the calculations to be
correct. Now, some of the values have changed for one cell and the range of
values available is dependent on the choice made; refer to the chart below:

Value in A1 Value in A2
$500 and less Up to $1,000
$600-$1,400 Up to two times the value
$1,500 + Up to $3,000

Ideally I want one of 3 drop down boxes to appear depending on the value in
A1 but I don't know how to do this. The increments are in $1,000. I need to
maintain the user interface and not allow "free input."

Thanks for your help.