The most common style of curtain is the pinch pleat drape. Style is one of the first things to consider. This is determined by the style of the furniture you choose, the size and shape of your windows and even the architecture of your home.
A contemporary version of the tab top drape would be the grommet top. A grommet is a hole in the fabric, surrounded by a metal ring.
Rod pocket panels are a very inexpensive window treatment. A bag made of fabric on the top of the curtain and a rod and slid through the wall.