no one likes naked windows
I decided to use standard flat bed sheets. My husband had some sheets that he bought to use for make shift curtains in his bachelor days. I can't remember the exact price of the sheets, but I am for certain they were no more than $5 at the very most. My husband had used standard tension rods to hold up his curtains so we used those. We also bought some cafe rods (the simple little ones that have a hook on either end of the window and the rod sits in it) because we have some bigger windows.
Once again, I broke out my sewing machine and got to work. I laid out the sheets and folded them in half longways. I then cut them in half with ordinary kitchen scissors to make panels. The best part of using sheets: they are hemmed already, you only have to hem the side you cut! I then sewed a small hem on the unfinished side. I used the top part of the sheet, with the folded down looking part as a guide for making the pocket for the rod to slip into. I folded down the top to the 'folded over edge' and sewed a straight line making the pocket. My husband so graciously fought with the curtain rods so that I didn't have to. What a guy! To make the tension rods look like cafe rods we bought the brackets separately (all of my supplies are from Wal Mart).
The window pictured is a small window, much to small for two panels. All of my other windows have two panels. The panels are a little long for our windows and puddle (pile up at the bottom) quite a bit. However, we have furniture in front of most all walls, so no worries for us. Though, with children you might want to cut and hem it so no one trips! (Trust me, this happens...I have the same treatment in our bedroom and my husband has!) You might also think about hanging the rods higher and adding a valance to cover the empty wall space. Doing so will add height to your room!
Don't stop with this simple design, add a button border to the top or some ribbons as tie backs. Get inspired, create something marvelous!