(AP) — Hundreds of inventors have flocked to Walmart's headquarters in Bentonville to find out if the country needs a few more secret sauces, prettier mouse pads or "instant hair gel" packets for the on-the-go clubber. The 500 businesses selected to take part in Walmart's fourth annual "Open Call" Wednesday have already been offered spots on the company's online portals, as it battles Amazon for billions of dollars in revenue. Visits with Walmart's marketing team, though, could land any number of entrepreneurs shelf space in nearly 4,700 brick-and-mortar stores. Bringing potential sellers to headquarters for Wednesday's crash course in marketing reinforces Walmart's path to making money. Former NFL football player Jarvis Green wants to sell restaurant-quality shrimp and seafood. Micah Specialty Foods, of Cleveland, features a kitchen marinade that originated in the West African nation of Ghana. Retail analyst Sucharita Mulpuru-Kodali said Walmart appears to have found a new way to address the breadth of Amazon, which has been expanding evermore into brick-and-mortar sales and announced this month that it would acquire Whole Foods for $13.7 billion, giving it a physical presence in many markets that could be used as a distribution hub.