In fact, in most of the deals undertaken by the stranger, the one thing that he can be certain of is that, when the time comes to pay, the price which has been definitely agreed upon has for one very plausible reason or another been increased.

NPR: Cracking the China Market, Then and Now

After months of negotiations, China's steelmakers agreed to pay up to double the price for the iron ore they buy from Rio Tinto, the biggest-ever annual rise in the cost of the commodity.

ECONOMIST: Business this week

Twenty women believed to be prostitutes were discovered with American agents or troops at the beachfront Hotel Caribe after one of the men allegedly refused to pay a previously agreed price for sex, sparking a row.

BBC: Obama criticises 'knucklehead' sex scandal agents

According to the indictment, Mobil agreed to pay Giffen a 5% fee that was understood to be included in the purchase price.

FORBES: Magazine Article