“three small window air units at walmart for 150.00 each.”
These are great deals—only need to use them for three months of the year (CT) and they work great—then you take them down for the colder months.
On of the best things I have done in the last few years is buy the heaviest insulated Blackout curtains for my four bedrooms and family room sliding door. I open those windows at night and close all the windows and curtains by 7am.
I run a couple window AC units only when it gets into the 90s here in NH.
Its what we do. if you leave the bedroom doors open where they are used, the cold air from those bedrooms cools the rest of the house here too. Michigan.