Wiktionary
rack jobber
n. (context business English) A wholesaler who merchandise#Verbs goods on racks in retail shops.
Wikipedia
Rack Jobber
A rack jobber (also known as a rack merchandiser) is a company or trader that has an agreement with a retailer to display and sell products in a store. The outlets for the products would be ones that traditionally don't stock such products such as gas stations, grocery stores and others not traditionally associated with the products sold. Often the products are of a budget variety.