I would really think hard about buying anything used that is that old. Most of the time you are just inheriting someone elses problem.
I prefer to rent compressors for blow outs. We own one, a 2006 sulair 185 and we rent 3 for 2 months. I understand that over time the rental fee adds up, but so does paying taxes, registration, insurance, and maintenance on the ones you own. It just sits for 10 months and takes up space. Cost of doing business I guess. Just something to think about.