Final answer:
A sales associate can best inform customers about the store's frequent shopper program by engaging with them personally, communicating the program's benefits clearly, and providing physical or digital material on the rewards and sign-up process.
Step-by-step explanation:
The BEST way for a sales associate to inform customers of the store's frequent shopper program is through a combination of personal engagement, clear communication, and direct marketing strategies. When a customer is checking out or being assisted, a sales associate should mention the program, highlighting its benefits and how it relates to the customer's shopping habits. Using a friendly and informative tone, the associate can explain the program's rewards and sign-up process, making it easy and appealing for the customer to join. Providing a physical or digital brochure or sign-up form can also be beneficial, allowing the customer to read more about the program at their convenience.