How about this Lorex 4 camera analog 1080p system (only $299):

http://www.costco.com/Lorex-4-Channel-HD-Analog-DVR-with-1TB-HDD%2c-4-1080p-Cameras-with-130'-Night-Vision.product.100237625.html

A friend has the 8 camera system in his business and it works great.

Remember that these pre-packaged systems do NOT include a monitor so be sure to pick up a cheap computer monitor or a monitor with HDMI input for the sharpest picture.