Main Success Scenario (or Basic Flow):
1 Customer arrives at a P0S checkout with goods and/or services to purchase.
2.             Cashier starts a new sale.
3.             Cashier enters item identifier.
4.             System records sale line item and presents item description, price, and running total.	Price calculated from a set of price rules.
Cashier repeats steps 2-3 until indicates done.
5.             System presents total with taxes calculated.
6.             Cashier tells Customer the total, and asks for payment.
7.             Customer pays and System handles payment.
8.             System logs the completed sale and sends sale and payment information to the external Accounting (for 	accounting and commissions) and Inventory systems (to update inventory).
9.             System presents receipt.
10            Customer leaves with receipt and goods (if any).

Extensions (or Alternative Flows):
7a.           Paying by cash:
1.     Cashier enters the cash amount tendered.
2.     System presents the balance due, and releases the cash drawer.
3.     Cashier deposits cash tendered and returns balance in cash to Customer.
4.     System records the cash payment.