How to repair home appliance signs to attract people?

The signboard says that home appliance repair is free for the first time, and only costs are charged, which is more attractive to customers. If a home appliance is broken, then someone will contact you to repair it with a try. At this time, you must stick to your promise, make home repairs for free, and only charge the cost, so that people who have repaired home appliances in your store will promote you to an acquaintance.