Roman shades! Bottom-up will provide the most light- looks like you have enough privacy. They're pretty easy to make if you're handy.

You might also try double pocket panels with tension rods- very inexpensive.

inside

Here's an even simpler solution to the windows. Tension rods with rings and clips. You can hang one cut end, folded if you don't have access to a sewing machine. The sides of the fabric will be selvage and the bottom again raw if you don't have access to a sewing machine. A tightly woven fabric, yet light in weight won't unravel. They will need to be hemmed or finished in some manner before you launder them however.