Dic: bargain with, bargain over, bargain for

bargain (over someone or something) (with someone): and also bargain (for someone or something) (with someone)

to negotiate with someone about obtaining someone or something.

• I refuse to bargain over money with Dan.
• We will bargain with the supplier over prices.
• You can't bargain over Claire with Jeff as if she were a car!
• They prefer to bargain with individual clients, for cash.
• Shop in small local markets and don't be afraid to bargain.

CF. bargain for something (and also bargain on something) : to plan for something; to expect something.

If you have not bargained for or bargained on something that happens, you did not expect it to happen and so feel surprised or worried by it.

• The effects of this policy were more than the government had bargained for.
• We knew the project would be difficult, but we didn't bargain for this kind of trouble.
• I bargained on an easier time of it than this.

.... McGrow-Hill Idioms, Cobuild