The price depends on functions. Whether it's wireless or not, with zoom, pan or tilt function or not. I'm using two wire IP cam with audio (without zoom, pan or tilt) which cover the whole living room, dining room and kitchen. It costs $1300 each. For others with zoom, pan and tilt, it costs more than $2k.
Level One, bought from Golden, Sham Shui Po.
One more thing, I use static camera because I'm too busy to look at the camera during office hour. So the zoom, pan and tilt function is meaningless to me. I use office PC and bundled software to record the video and check when free. I have saved all these video to DVD and keep it as part of my BB's record. It's about 1.5GB each day.
I also bought from Golden (Centralfield), but Vivotek PT7137, Wireless with Pan/Tilt/Digital Zoom, support RTSP (browse from 3G phone), at $2100 per unit. Bundled with software for video recording with PC.