For a regular double hung window I charge $5 for the whole package, screen, sill and interior exterior cleaning. 2nd floor, make it $6. To make it clear, if you have a two story house with 20 windows expect to pay around $110-$120.
Storm windows, the price is double. Triple the work, double the price. You still win.
Unusual windows? Really high windows?
Feel free to call me. I will gladly come by and take a look and give you a price.