A method of doing business in a retail environment employs a patronage incentive system incorporating a rounding up saving software program which provides a customer making a purchase at a point-of-sale terminal of participating retailers with an option to round up the price of purchase to the nearest dollar (or higher), to credit the difference between the rounded and the retail price to an account once the purchase is made, and to invest the savings into a single predetermined mutual fund. The rounding up program establishes a personal account for each customer, establishes a cumulative account with the single mutual fund, interacts with the customer, and, upon the request of customer, provides the customer with the information regarding his/her account current and/or prospective.