White vinegar is a cheap and eco-friendly cleaning substitute. And it actually works better than Windex. Windex is about $2.40 a pint while vinegar can be bought in giant containers from grocery stores for $.99 a pint.
So, save your Windex spray bottles because you’re never going to need them again. Fill them with a mixture that is one tablespoon of white vinegar to one quart of water. Spray them on your windows and wipe the panes with newspaper to avoid streaks.