Each summer ââ?¬â? and sometimes into the year ââ?¬â? a college-age army nearly 150,000 strong spills out across the nation hawking wares for such companies as Southwestern, Mary Kay, Avon and Cutco Cutlery. Some go door to door. Many others set up appointments or hold ââ?¬Å?product partiesââ?¬Â to reach customers.For the companies, the students provide a windfall.