The Sales Start Date is used to select the starting date for the sales period we are basing our budget on. If you are creating a sales budget for the year 2007 based on the previous years sales you should set your sales start date as January 1, 2006. If you are creating a budget for Q2/2007 you should set your sales start date as April 1, 2006. This field is especially useful when creating budgets based on past sales history since it tells the system where to start.