Overflow Error:

[Hack]

It worked fine for me. You said you were dealing with six digit numbers so I used 999999 and had no problems.

I do have one question though. Why is intRentalPrice (which implies integer, lng implies a Long) being set to a string? "0" is string...0 is an integer. Here is what I tested

Private Sub Command1_Click()
Dim lngRentalPrice As Long
If txtRentalPrice.Text = "" Then
    lngRentalPrice = 0
Else
    lngRentalPrice = CLng(Val(txtRentalPrice.Text))
End If
MsgBox lngRentalPrice
End Sub