Beverage Air won't cool

I am seriously considering buying this unit for $325.00
It is ten years old. I figure the parts alone are worth it, even if I can't get the compressor to come alive. Any ideas on the cost of a compressor for this unit. What do you guy's think? Should I buy it?
Here's the ad from Craigslist.

This is a commercial grade Kegerator made by Beverage Air. I am the origional owner. Note that this Kegerator no longer cools. I replaced the thernostat and that did not solve the problem. I assume the compressor needs to be charged or replaced. However, at $350.00 this package is a steal! The European Flow Control Faucet alone is worth $90.00 not to mention all the other extras that I'm throwing in. I will include a 5 Liter Cleaning Bottle, Spanner/Hex Nut Wrench, Chrome Tap Handle, Plastic Tap Handle, Ceramic Tap Handle, Micro Matic Premium Duel Gauge Regulator, Micro Matic D System Coupler, Tank Wrench, and a standard Chrome Faucet. 15 lb Co2 cylinder.

Well I picked up a working Bev Air(DD56 I think) a while back and used it for a few months and the compressor took a dump. It was an R12 unit. I picked up an NOS compressor on eBay for $50 and then had to pay $250 to have it installed. I stole that compressor at $50. In my research I found that it could possibly be the capacitor on the motor that has gone bad and can be replaced fairly reasonably. If the motor still has a little life in it, you can put a kick start on it which from what I understand is an amped up capacitor. My suggestion is that if you are ok with spending an extra $3-400 then go for it but if not spend the cash and have it looked at by a professional and proceed from there. Personally I would stay away from it unless it was in perfect condition and the money isn't a huge deal.

Thanks for the advice DeBrewer!