A process for increasing profits of a business engaged in the purchase of large numbers of products and/or products of volatile pricing from numerous vendors that operates to identify pricing errors, preferably typically before payment, by automatically reviewing all invoices typically in the order they are received to determine a best system price for each line item of each invoice by reference to pricing factors such as volume discount, seasonal pricing, price protection, commodity pricing, competition pricing, and cash discount recorded in memory for the subject item and reference to payment history data, accounts payable data and invoice data. From the pricing factors and associated data, a best system price is determined and compared to the invoice price for the item so that pricing errors are automatically uncovered and, if appropriate, flagged to identify the same as an exception for warning or notification.