A sail is a piece of fabric that is attached to a boat, and it safely fills up with the wind and keeps the boat going. It could also refer to an actual boat ride. It may mean something is meant to be driven by the wind, such as a frisbee sailing in the air toward an eager dog. Blades in a windmill are called sails, and it can be a term used to illustrate the flight or the wings of the bird.
On the other hand, a sale refers to exchanging goods or services for money or other currency. There is a distinction between a sale and an exchange of goods or services for other goods or services. The word can be used to describe the decrease in price for an item. If something is being sold for a reduced sum of money from its original price, it is called a sale.
When you say sail, this refers to a verb that you will do when you are about to get into the ocean or the sea aboard a boat. Sailing can take you to different places that may be near or far from where you have started. When you say sale, this can refer to items that are available to be purchased by people.
Sale can also mean that items that used to be priced higher will be priced in a much lower account. Taking advantage of sales will allow you to purchase more items with the budget that you have. Or you can also save up on money and use the money on purchasing other things instead.