A while back I bought a Uniden all in one camera system. It included 4 wireless cameras, a 7" monitor with the wireless receiver built in, and all the cables & software. Whole thing cost $100 on eBay.
Picture quality was okay, it included IR for low light situations and was pretty easy to use. The 7" monitor required to be plugged in at all times, but there was also a 3.5" monitor with a built in battery so that you could put it in your shirt pocket and take it on the go... Very handy baby monitor.
One nice thing about it, both the 7" & 3.5" monitor had an A/V output to display the image on any TV of my choosing. You could display one or all four cameras on the screen at one time on the 7" only.
