Update to first part.
Wifi IP CAM didn't come down in price by a lot. Direct from dhgate, it is closer to the $50 mark rather than the $100 mark. You need a portable or desktop to record the video automatically. That's not bad when you are sleeping or away from the desk.
DVR changes a lot since last time. Even in the past, it doesn't make sense to have a CMOS CAM, turns the images into analogue signal, then the DVR re-digitize the image, compress and store it in hard disk. Now, many people don't have NTSC and PAL anymore. HDMI output for a CAM is too much. So it only make sense to integrate the CAM with the DVR.
They became cheap small HD camcorders. They are everywhere but they are just not for security CAM application. You need overwrite or cycle recording. So you never need to change "tapes" or SD cards. The other very desirable feature is software motion detection - which saves a lot of storage space.
There are one in dhgate exactly that. They say it's for cars. The price is not a lot more than $50.
My old DVR is going strong. Similar things are still on sale but became more expensive now, a lot more than $50. The output of my old CAM's are still NTSC. HDMI output will be a lot more expensive.