It looks like you have a Haier kegerator, there....mine looks exactly the same. Here's how I look at it:
Working Kegerator w/out Co2 tank: $100-$125
Empty 1/6 sanke keg: $50
Sanke Coupler: $20
I bought one of these off CL and paid $75 cause it was inoperable, but mine had a full Co2 tank. Here's the link with some pics and the model number:
https://www.homebrewtalk.com/f14/my-75-craigslist-find-417491/
If it is the same base model, you should be able to get 3 corny kegs in there, and change it over to a 3 tap tower. I recently converted mine over to a dual tap, and love it. I found a used tower and faucets for $70, a dual regulator setup for $25, and sold my old tower for $50. If you want some pics after the conversion, let me know.
As far as the price goes, it all depends on what the area demands. I have seen people on here get better deals, but GA doesn't appear to be a dumping ground of surplus brewing/kegging equipment. For instance most single tap kegerators around here go for around $250 on average without a keg. The cheapest i have gotten ball lock kegs if $45 and the highest was $60, and I have seen folks snag them for as low as $25. I would see if he would take $150 for it and point out the fact that it needs a Co2 tank, the cost of one and what Yooper said about the regulator possibly not working, as you have no way of testing it. Fittings and lines should be relatively inexpensive.