Zahara is good for the bottom line. With departmental heads approving spend before it's committed, you will be able to catch wastage and detect potential fraud - whether thats internal or external. You can control pricing and the choice of suppliers. Zahara is about moving the approval process away from the Invoice - when the service or goods have already been delivered, further forward, to when an individual wants to buy something. With the option to use Budgets, you can also empower buyers to spend within their limits yet approve over-spend automatically.
Purchase Orders are the formal and efficient way to tell your suppliers what to supply, when to supply it, and at what price you expect to be charged. They are a very efficient way of improving the buying process. Zahara makes buying easier by removing any need for paper-based requisition forms or manual recording of orders in spreadsheets. Zahara compliments your existing accounts system to provide layered approval workflows so you can empower your staff, yet control the buying. Approvers can approve on-the-go by email, or login to Zahara from any device.
"Ohh, but we use SAP..." - It doesn't matter what accounts system you use. If you haven't enabled the PO module on your accounts system - which quite frankly assumes you are buying raw materials and widgets, as opposed to every days expenses, then you will find Zahara considerably easier to use, considerably cheaper to adopt and much faster to deploy.