sale 
(sāl)
(sāl)n.
Idioms: 1.
a. The exchange of goods or services for an amount of money or its equivalent; the act of selling: The sale of such a nice house should be easy.
b. A selling of property to the highest bidder; an auction.
2. An offer or arrangement in which goods are sold at a discount: The store has a sale on winter coats.
3. sales
a. The business or activity of selling goods or services: She works in sales.
b. The number of items sold or the amount of money received for a number of items sold: Sales are better than expected.
for sale
Available to customers: a store where pets are for sale.
on sale
1. Available to customers: That vegetable should be on sale at your local grocery.
2. Available to customers at a special discount: Bathing suits are on sale.
[Middle English, from Old English sala, from Old Norse.]