The 2002 US farm bill has the highest price tag ever, and the cost could grow as the bill moves producers further away from market-oriented agriculture and free trade, said a Purdue University agricultural economist. "The US$180bn budget for the farm bill assumes that commodity prices will improve after four years," said Allan Gray, assistant professor of agricultural economics. "That's questionable, given that payment mechanisms in the farm bill will likely encourage overproduction that will depress prices."