Can i get the hotel near the HKIA very easily? My budget is not more that 100USD per night.

Well, I found the hotels nearby the airport. However, the fares are over 100 USD per night. Maybe you are suggested to stay at Plaza Premium Lounge at HKIA. It's the one that serves all passengers and airport users. The opening time are 24 hours. It provides convenient facilities such as hot showers, all day food and beverage, beauty and massage services.
The address is Boarding Gate No.35, West Hall, 6F, Departure Hall, T1.
I remember that the prices are 400 HKD for 2 hours, 500 HKD for 5 hours and 600 HKD for 10 hours.
You are suggested to dial (+852) 3559 1108 and consult more details.