got a question ragarding A/C

[N/A N/A]

I have a small tenant house that I could purchase for about 30k. Its really not in bad shape just needs some paint, new carpet, and new stove/fridge. It also has central heating. Its also on 3 acres of land. My only concern is that it doesnt have central air conditioning. Its got the little ac units in the windows. How much do u think it would cost me to put in central AC. Can they run it through the same ducts as the heat or would they need to put in new ducts? Thanks alot.

samueljm