People who keep bees commercially keep them to make a living. They take them far and near to fields and farms so the bees can pollinate the crops they are visiting. This is their most-often discussed activity, now that they are dying in droves and the food they help produce could possibly be reduced. Probably the most cited statistic in the entire Colony Collapse Disorder business is the Cornell study that says honey bees help contribute somewhere in the neighborhood of $15 Billion worth of food production in the U.S. on an annual basis. This figure is over eight years old (done in 2000), so with inflation that figure should rightly be moved up to just short of $19 Billion today. That's the real number here.
This figure, however, doesn't include the money paid to beekeepers for all this effort. A quick calculation of that number, without real good data available would probably underestimate this amount, but you would be close if you counted the number of colonies used to pollinate crops in the U.S. in a season, and the number of crops those colonies pollinated.