Discount house windows can be found at Habitat For Humanity ReStore's, major home improvement retailers, local building suppliers and Craigslist.org. Common sizes such as 24 by 36 inches are the easiest to find at major retailers whereas custom home suppliers are more likely to have odd sized windows that customers have returned.
Local ads on Craigslist and newspapers often have windows for sale that are leftovers from a remodel project or renovation. Used windows can still have a lot of life left in them so they should be considered as a cost effective option. Ebay.com sometimes has discounted windows.
Major home improvement stores usually have a surplus section of windows that were purchased by mistake. Returned windows are often sold at a steep discount, especially if they are not a standard size. Sometimes large retailers offer coupons that can be used for additional savings. A local glass company or building supply store may have some leftover windows available at discounted prices. Seasonal sales in the spring and fall can help cut the cost of window replacement. Larger stores do not always have the best price, so it is important to get window quotes from more than one retailer before purchasing.