Of course it depends on the location because Sai Kung/Clearwater bay area have a wide range of rent. If is along Hirams Highway, it is not bad (with sea view, it is a good price). If is along Sai Sha Road, then it will not ba a good price. As I know at Che Keng Tuk Road one apartment same condidtion as the one you are going to look is offering $7,500. (On the roof can see a bit of sea)
I will suggest don't make the decision too quick because that area have planty of choices. You can go to Sai Kun Town and can find many Estate Agents. Take your time to find a suitable one for you.