1
general::
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."
American Heritage Idioms
2
general::
Phrase(s): drive a hard bargain
to work hard to negotiate prices or agreements in one’s own favor. • All right, sir, you drive a hard bargain. I’ll sell you this car for $12,450. • You drive a hard bargain, Jane, but I’ll sign the contract.
McGrawhill's American Idioms And Phrasal Verbs