BI software isn't all that expensive, under $100, and support is inexpensive as well. A machine to run it on, assuming a dedicated machine, can be had as a re-furb for under $400. If you already have a decent i5 or i7 desktop collecting dust it doesn't cost anything. Adding drives for recording costs a couple of hundred bucks, but most packaged systems that use NVRs, like the Costco stuff, have too small a drive in them anyway. PoE switches aren't all that expensive, under $100 for unmanaged 8 port or $200 for a managed 24 port. The real killer is cameras. I have one that was almost $200, low light with a 12X varifocal lens, but the rest were in the $120 range. Keep in mind a varifocal is not a zoom. It's meant to be set at installation and left alone while a zoom is made for, more or less, continuous focal length changes. The pan-tilt-zoom stuff seems nice, especially with automated tracking and pre-set positioning, but they get expensive really fast, $350 and up to well over $1K-$5K depending on zoom and bells and whistles. Getting CAT5 or CAT6 out to them can be problematic, but it's a one time thing. I already had a good RJ crimper and cable tester from my networking days so I didn't need them and with years of experience with alarm system and network wiring it isn't hard to do.
I will say that I learned, the hard way, that buying "inexpensive" cameras is a waste of money. The video can show you what happened, but not who did it.
I will say that I learned, the hard way, that buying "inexpensive" cameras is a waste of money. The video can show you what happened, but not who did it.