There is a flat rate of 50 euros per day and a minimum charge of 250euros. You are welcome to plead poverty, family, freindship, or willingness to work on the house or bring nice things. All these could get discounts of up to 100% but don't push your luck.
We now charge an additional 30 euros for the house to be prepared after you go and the bedding and towels washed but this only covers hoover and dusting. Don't leave food, rubbish or dirty washing up.
If you want a bigger house or would like to stay in the heart of the Rhodes town then I can recomend other people who rent houses, although they are much more expensive and much less charming.