Have a check box called 'rush orders'
Have a currency field called 'unit price'
Want value in unit price to increase 30% if check box is selected.
Any help is grateful.

I've never used a currency format explicitly before, but here is how I would approach it.

You need a third box, maybe invisible, that is the REAL price of the item.

Resources:

[Rush Orders]: checkbox, True or False
[Unit Price]: text box, Currency format
[Real Price]: text box, Currency format, .visible = false

On the form, in a couple of places, put this snippet of text (I'll tell you where in a second...)

If [Rush Orders] Then
[Unit Price] = [Real Price] * 1.3
Else
[Unit Price] = [Real Price]
End If

Now, put this code in event routines as follows:

1. Form_Current
2. Rush_Orders_Click
3. Unit_Price_GotFocus
4. Unit_Price_LostFocus

This code did not work. Do you have another method?