We quote just the daily rates to keep things simple for our readers and because that is the nearest we can get to a common rate that can act as a comparitor between properties. However most properties offer weekly rates and/or monthly rates. The discount will vary depending upon the popularity of the property concerned, the length of time you want the property for and the time of year. Please be warned that popular (i.e. good) properties are unlikely to give that much of a discount during the peak months of January and February.
The daily rate will help you determine those properties that are likely to be in your budget. Then, send an enquiry to the property asking for a quotation for your intended dates.