We are threatened that the cost of lettuce will rise precipitously if we don't continue to import Mexican agricultural workers. But a farm worker gets only 6 or 7 cents out of a $1 head of lettuce, so even if the pay doubles consumers would hardly notice the difference.

On the other hand, the costs the taxpayers are forced to pay for social benefits for low-paid workers are astronomical. The National Research Council reports that an immigrant to the United States without a high-school diploma consumes $89,000 more in government services than he pays in taxes during his lifetime.

http://www.eagleforum.org/column/2006/apr06/06-04-26.html