Microsoft Access field adds 1 - ms-access

Question

I have a strange bug where my currency field adds $1 to every entry. I have the values stored in a table, and use a lookup to get those values
ReducedLunch = DLookup("[Cost]", "LunchCost", "[ID]=2")
NormalLunch = DLookup("[Cost]", "LunchCost", "[ID]=1")
Milk = DLookup("[Cost]", "LunchCost", "[ID]=4")
NoLunch = DLookup("[Cost]", "LunchCost", "[ID]=5")
Then I have some VB code to write the appropriate value to the database field...
If (rs!TodaysLunch = "Lunch" And rs!FreeLunch = False And rs!ReducedLunch = False) Then
DailyCost = NormalLunch
rs.Edit
rs!TodaysCost = DailyCost
rs!Balance = rs!Balance - DailyCost
rs.Update
End If
If I put a msgbox command before the Endif to show the DailyCost value it shows the correct value at this point, however when I actually write the data back to the table
DoCmd.RunSQL "INSERT INTO Lunch (StudentID, DateOfLunch, TypeOfLunch, Cost) SELECT [ID],[TodaysDate],[TodaysLunch],[TodaysCost] FROM Students"
TodaysCost has added an extra dollar. I've checked and double checked everything, but can't find where it's getting this mystery value from. I tried setting DailyCost to zero (it's defined as currency), but it still writes back the value + 1.
Here is my complete code and the msgbox command near the end is at what point a 1 is added...
Dim DailyCost As Currency
Dim ReducedLunch, NormalLunch, Milk, NoLunch As Variant
Dim rs As Recordset
Dim db As Database
DailyCost = 0
Set db = CurrentDb()
Set rs = db.OpenRecordset("SELECT * FROM Students")
ReducedLunch = DLookup("[Cost]", "LunchCost", "[ID]=2")
NormalLunch = DLookup("[Cost]", "LunchCost", "[ID]=1")
Milk = DLookup("[Cost]", "LunchCost", "[ID]=4")
NoLunch = DLookup("[Cost]", "LunchCost", "[ID]=5")
Do Until rs.EOF = True
'Check for free or reduced and get price
If (rs!TodaysLunch = "Lunch" And rs!FreeLunch = True) Then
DailyCost = 0
rs.Edit
rs!TodaysCost = DailyCost
rs!Balance = rs!Balance - DailyCost
rs.Update
End If
If (rs!TodaysLunch = "Lunch" And rs!ReducedLunch = True) Then
DailyCost = ReducedLunch
rs.Edit
rs!TodaysCost = DailyCost
rs!Balance = rs!Balance - DailyCost
rs.Update
End If
If (rs!TodaysLunch = "Lunch" And rs!FreeLunch = False And rs!ReducedLunch = False) Then
DailyCost = NormalLunch
rs.Edit
rs!TodaysCost = DailyCost
rs!Balance = rs!Balance - DailyCost
rs.Update
End If
If (rs!TodaysLunch = "Milk") Then
DailyCost = Milk
rs.Edit
rs!TodaysCost = DailyCost
rs!Balance = rs!Balance - DailyCost
rs.Update
End If
If (rs!TodaysLunch = "Lunch XtraMilk") Then
ElseIf (rs!ReducedLunch = True) Then
DailyCost = ReducedLunch + Milk * 2
ElseIf (rs!FreeLunch = True) Then
DailyCost = FreeLunch + Milk * 2
ElseIf (rs!FreeLunch = False And rs!ReducedLunch = False) Then
DailyCost = NormalLunch + Milk * 2
rs.Edit
rs!TodaysCost = DailyCost
rs!Balance = rs!Balance - DailyCost
rs.Update
End If
If (rs!TodaysLunch = "No Lunch") Then
DailyCost = 0
rs.Edit
rs!TodaysCost = DailyCost
rs!Balance = rs!Balance - DailyCost
rs.Update
End If
'Set date to today
rs.Edit
rs!TodaysDate = Date
MsgBox (rs!TodaysCost) 'Point where 1 is added
rs.Update
rs.MoveNext
Loop
rs.Close
Set rs = Nothing
DoCmd.RunSQL "INSERT INTO Lunch (StudentID, DateOfLunch, TypeOfLunch, Cost) SELECT [ID],[TodaysDate],[TodaysLunch],[TodaysCost] FROM Students"

Answer 1

Make sure that TodaysCost is not Long Integer.