Walmart has Frigidaire 10,000 BTU window air conditioner model FFRE1033S1 (Energy Star certified) on sale for $216.42 at this page . Price will be visible in cart.
Other Frigidaire units are also on sale, but this particular one has the biggest discount.
Discover cardholders can get another 5% cashback on Walmart.com orders.
Most other retailers have it for $320-$340.