D.P.
We have used VRBO many, many times.
I was able to negotiate a rate on O. unit--actually, when I waffled a little bit about the weekly rate (it was a 'call for rates' listing) the owner asked what I thought I would be comfortable with! So yes...I did get a better rate than originally quoted--but I think you'd have better luck negotiating on a unit/week that is unbooked and coming up very soon! They'd rather rent it at a reduced price than have ZERO income for that week. Good luck!