If your window has no casing but a blind, mini-blind curtain rod brackets are also a good alternative to fixed brackets. On a scale of 1 to 10, I'd give these options 9 or 10.

Kwik-Hang Single Curtain Rod Brackets ($13) Typically, curtain rods are supported by mounting brackets that sit several inches above the top of the window frame. No drill curtain rod brackets fit ...