VBA to add totals and formula to multiple sheets - excel

Question

I have an excel sheet with around 200 work sheets each containing a list of products sold to a company.
I need to add
A total at the bottom of row D-G where the bottom can be a different value. I.E. E4
below the total a formula based on the total. I.E. if E4 (being the bottom of the above row) is below $999 the display text "samples", if between 1000-3000 then multiply E4 by 2%, 3001-7500 x 5% etc.
I need to be able to add it to the entire workbook easily using vba. Since I must do this to numerous ss it would literally save me 15-20 hours a month.
Edit:
So I have something that seems to be the right path.
Sub Split_Worksheets()
Dim rRange As Range, rCell As Range
Dim wSheet As Worksheet
Dim wSheetStart As Worksheet
Dim strText As String
Set wSheetStart = ActiveSheet
wSheetStart.AutoFilterMode = False
'Set a range variable to the correct item column
Set rRange = Range("A1", Range("A65536").End(xlUp))
'Delete any sheet called "UniqueList"
'Turn off run time errors & delete alert
On Error Resume Next
Application.DisplayAlerts = False
Worksheets("UniqueList").Delete
'Add a sheet called "UniqueList"
Worksheets.Add().Name = "UniqueList"
'Filter the Set range so only a unique list is created
With Worksheets("UniqueList")
rRange.AdvancedFilter xlFilterCopy, , _
Worksheets("UniqueList").Range("A1"), True
'Set a range variable to the unique list, less the heading.
Set rRange = .Range("A3", .Range("A65536").End(x2Up))
End With
On Error Resume Next
With wSheetStart
For Each rCell In rRange
strText = rCell
.Range("A1").AutoFilter 1, strText
Worksheets(strText).Delete
'Add a sheet named as content of rCell
Worksheets.Add().Name = strText
'Copy the visible filtered range _
(default of Copy Method) and leave hidden rows
.UsedRange.Copy Destination:=ActiveSheet.Range("A1")
ActiveSheet.Cells.Columns.AutoFit
Next rCell
End With
With wSheetStart
.AutoFilterMode = False
.Activate
End With
On Error GoTo 0
Application.DisplayAlerts = True
Dim colm As Long, StartRow As Long
Dim EndCell As Range
Dim ws As Worksheet
StartRow = 3
For Each ws In Worksheets
Set EndCell = ws.Cells(Rows.Count, "c").End(xlUp).Offset(1, 1)
If EndCell.Row > StartRow Then EndCell.Resize(, 4).Formula = "=SUM(R" & StartRow & "C:R[-1]C)"
Set EndCell = ws.Cells(Rows.Count, "D").End(xlUp)
If EndCell.Row >= 1000 Then
Range(J2) = Formula = ((EndCell.Row) * (0.05))
Range(J3) = "5% Discount"
ElseIf EndCell.Row >= 3000 Then
Range(J2) = Formula = ((EndCell.Row) * (0.1))
Range(J3) = "10% Discount"
End If
Next ws
End Sub'
Just need to figure out how to display the results and text to the right cells (J2 in this case)

Answer 1

I will supply the logic and all the references you need to put this one together; and will let you try to put it together on your own :). Come back for more help if needed.
You need to loop through all the worksheets in your workbook (Microsoft Tutorial)
You need to find the last row for the given columns (Online tutorial)
You need to use an IF statement to choose which formula to use (MSDN reference)
UPDATE
What's wrong with your code is this line :
Range(J2) = Formula = ((EndCell.Row) * (0.1))
What you're telling the computer is :
Multiply EndCell.Row by 0.1 (which has the number of the row below and to the right of the last cell in column C)
Compare Formula with the result previously obtained
Store the result of that logical expression at the range stored in variable J2
First of all, what you want is to put the result of the equation, and want to change J2 to "J2" so it gets the cell J2, instead of the what's contained in J2 (which has nothing at that point)
Also, you seem to say that you're not getting the right cells, maybe it is caused by this :
Set EndCell = ws.Cells(Rows.Count, "c").End(xlUp).Offset(1, 1)
In that line, you're finding the last cell of column C, but then you select the cell below, and to the right of it.
There are so many things wrong with your code it's hard to say what's not working properly.