Excel 2007 : eBay comission code, various percentages...

You can use a user defined function.

Paste the following into a new module sheet in the VBA editor (Alt F11). (Insert - Module)

Function EBAyCommission(Cell As Range)
PriceRemaining = Cell.Value
Do While PriceRemaining > 0
    Select Case PriceRemaining
        Case PriceRemaining > 300
            EBAyCommission = 0.015 * (PriceRemaining - 300)
            PriceRemaining = 300
        Case Is > 200
            EBAyCommission = EBAyCommission + (0.02 * (PriceRemaining - 200))
            PriceRemaining = 200
        Case Is > 100
            EBAyCommission = EBAyCommission + (0.025 * (PriceRemaining - 100))
            PriceRemaining = 100
        Case Is > 30
            EBAyCommission = EBAyCommission + (0.03 * (PriceRemaining - 30))
            PriceRemaining = 30
        Case Else
            EBAyCommission = EBAyCommission + (0.0525 * (PriceRemaining))
            PriceRemaining = 0
    
    End Select
Loop
End Function

You should then have a new function called EBAyCommission available on your spreadsheet..