A sale is what occurs whenever an object or service is given in return for a payment of money. The sale of your old bike will happen more quickly if you price it at $50 instead of $500.
You can talk about the sale of your next door neighbor's house, and you can also describe the house as "for sale," or available to be purchased. When a store has a sale, it means goods temporarily cost less than usual — you can also say that things at that store are "on sale." The word sale comes from the Old English sala, from a Germanic root.