Question : Rounding up or down by 20 cents in access

I have a field that I calculate:
 Private Sub AM_TIME_LostFocus()
AM_COST.Value = AM_TIME * 0.5 * 0.4
AM_RATE.Value = 3.62 + AM_MILES2 * 2.2 + AM_TIME * 0.4 + AM_COST
End Sub

Based on am_rate I need to round up or down according to the following:
$0.01 and $0.10       round down to $0.00
$0.11 and $0.19       round up to $0.20
$0.21 and $0.30       round down to $0.20
$0.31 and $0.39       round up to $0.40
$0.41 and $0.49       round down to $0.40
$0.51 and $0.59       round up to $0.60
$0.61 and $0.69       round down to $0.60
$0.71 and $0.79       round up to $0.80    
$0.81 and $0.89       round down to $0.80
$0.91 and $0.99       round up to $1.00
Please help I am very new at this. Thanks

Answer : Rounding up or down by 20 cents in access

Private Sub AM_TIME_LostFocus()
AM_COST.Value = AM_TIME * 0.5 * 0.4
AM_RATE.Value = 3.62 + AM_MILES2 * 2.2 + AM_TIME * 0.4 + AM_COST
Select Case AM_RATE.Value - Int(AM_RATE.Value)
    Case Is <= 0.1: AM_RATE.Value = Int(AM_RATE.Value)
    Case Is <= 0.3: AM_RATE.Value = Int(AM_RATE.Value) + 0.2
    Case Is <= 0.5: AM_RATE.Value = Int(AM_RATE.Value) + 0.4
    Case Is <= 0.7: AM_RATE.Value = Int(AM_RATE.Value) + 0.6
    Case Is <= 0.9: AM_RATE.Value = Int(AM_RATE.Value) + 0.8
    Case Else: AM_RATE.Value = Int(AM_RATE.Value) + 1
End Select
End Sub