You can get free Rain-X Products From Walmart. Get select Rain-X products for free with this mail-in rebate! Click the ‘View Details’ button for the rebate and print out the mail-in rebate form. Get Rain-X Waterless Car Wash & Rain Repellent, Rain-X 2 in 1 Exterior Detailer or Rain-X Water Repelling Fast Wax. Purchases must be made at Walmart stores between 05/01/2018 to 06/30/2018. Request Sample Now!