dick ‧ er /ˈdɪkə $ -ər/ BrE AmE verb [intransitive] informal especially American English
[ Date: 1800-1900 ; Origin: Perhaps from dicker 'group of ten (animal skins)' (11-19 centuries) (from the exchanging of skins for other goods) ]
to argue about or discuss the details of a sale, agreement etc
dicker about/over
Politicians in Washington are still dickering over the budget.