Every time I go to HK I usually stay at Chungking mansion. It's cheap (with rooms starting from 100kuai per night, therefore you'll get the service you're paying for, don't expect any extra comforts) and the location (Nathan road in Kowloon) is very convenient, both if you're doing the visa run thing or just want to enjoy your time there as it is 5 minute walk away from the ferry station.
Have a safe trip!
Thanks Dario. I have booked one hotel in Chungking Mansion. Looking forward for the trip !! Will update my experience :)