Be severe in negotiating a transaction, make an agreement to one's advantage. For example, It's more than I planned to pay, but you drive a hard bargain. This expression, first recorded in 1836, uses the verb drive in the sense of "forcefully carry through."

The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Company. All rights reserved.