If power is for sale, sell your mother to buy it. You can always buy her back again.
— Arabic Proverbs

If wisdom were on sale in the open market, the stupid would not even ask the price.
Unknown sale quote

No sale is really complete until the product is worn out, and the customer is satisfied.
— L.L. Bean

Every sale has five basic obstacles: no need, no money, no hurry, no desire, no trust.
— Zig Ziglar

A sale is not something you pursue, it's what happens to you while you are immersed in serving your customer.
— sale quotation by Unknown