This approach is encouraged by moneysaving expert in their Cheap Holiday Rentals guide;
http://www.moneysavingexpert.com/travel ... ay-rentals
Some quotes;
It definitely annoys.So the more folks you cram in, the better. If guests kip in the living room (check ahead if there are sofa beds), the savings can rocket.
Haggle for discounts
Once you've found a specific property, try calling or emailing the owner to ask if they can drop the price.
You could also try calling or emailing owners of similar properties nearby to see if they can beat the price.
Though remember aggressive haggling's usually a mistake, as it annoys them.
There are some good points in the guide though, especially with regards to protecting payments.