«اِلشِّرَا يْعَلِّمِ الْبِيعْ»

Standing on the buyer's side of a deal is treated as an apprenticeship in trade. Through bargaining over prices and inspecting goods, a person absorbs the tactics merchants use, so that later, when he sells, he already knows how such exchanges work.

More broadly, the saying holds that skill in one role grows from experience in its opposite. Watching how others handle you as a customer gives the knowledge needed to handle customers yourself.

Suited to talk about trade or bargaining, especially to encourage someone who has only ever bought goods but now wants to sell. It frames time spent haggling at other people's stalls as useful preparation instead of wasted effort.