Someone mentioned that minisplit systems are expensive. I found a unit here that is pretty reasonable.
MiniSplitShop.com :: One-Zone Mini Split :: Soleus (Heat Pump) :: 9,000 BTU Soleus Mini Split A/C + Heat Pump - 115 V
I doubt that I can get a rooftop unit for $400. My rooftop is getting weak and I want to use one of these. I just have to work out where I will put the compressor unit.