I had an interesting one the other day. I was in two minds about whether to do a one-way on an Avis rental. When I picked up the car, I clarified that I could change my mind, leave it somewhere else, and the one way charge would be £40. I had declined the additional insurances. The guy said he would waive the one-way charge if I took £13 (or thereabouts) of insurances. They're obviously paid an incentive on the insurance sales, but not on the one ways. Might be worth trying as a bargaining tactic...