Libman sponge mop refills are available at Walmart, Target and Home Depot retail stores. Mop refills are also sold online at these stores' websites and at Amazon.com.
As of 2015, Target, Walmart and Home Depot carry different selections of Libman refills. While Target only sells four types of Libman refills, Home Depot and Walmart sell over 15 types. Some of these refills are available in store, while others are only available online. Prices are comparable at all of these venues.
Amazon.com has the largest selection of Libman refills. While prices are lower for some varieties, others are more expensive than in physical retail stores.