What it is:
Backpricing is a method for pricing commodities, whereby the buyer and seller agree to buy/sell a commodity but set the price at a later date.
How it works/Example:
For example, let's assume that John wants to buy some corn. On July 1, he approaches Bill, who agrees to sell John 100 bushels of corn on September 30. John doesn't want to pay Bill the July 1 price, so the two of them agree that they will set the price on September 1. When September 1 rolls around, John and Bill backprice the corn and agree to conduct the transaction on September 30, as originally planned.