When is the best time to buy an Air Conditioner? When it's "off season".Good luck when it gets hot!
I have two window unit air conditioners for sale. Both are manufactured by Haier.
One is 10,000 BTU unit
Second is an 8,000 BTU unit.
10,000 BTU was used for one summer in Rhode Island (not a lot of summer to be had) asking $100
The 8,000 BTU unit has two years of use in R.I as well.
$80
My Guess is that you will get more use out of them in Illinois during your long summers