Replacement cushions for porch swings are available on Amazon.com, and at Lowe's and Walmart stores. A company called Garden Winds also makes custom and universal cushions for many of the top retail stores that sell porch swings.
Amazon.com, Lowe's and Walmart all sell many different types of porch swing cushions for standard sized porch swings. Many fabric and size options are available. As of 2015, these cushions are priced at anywhere from $50 to several hundred dollars.
Garden Winds sells replacement cushions for porch swings at Target, The Home Depot, Walmart, Big Lots, Lowe's, Sears and Kmart. The company sells universal cushions that fit most porch swings, as well as custom cushions. Prices start at about $100.