Case molding is by far the most simplistic choice for trimming out your windows. It is also the least expensive of your window trim options. Basic case molding, as of late December 2009, is about $3.99 per 7-foot piece. Case molding comes in a variety of styles such as plain, fluted and architectural designs. You may want to match other interior trim that you currently have around your door or ceilings.
Decorative window trim can make your home look elegant, giving it that finished look. At the same time, though, decorative window trim can be costly. Some pieces of trim are priced upward of $40 per 7- to 8-foot piece, as of late December 2009. Decorative molding may be made of wood or even plastic and comes in many different patterns and designs to suit your needs.
You may decide that you can't get the profile you want just by using one piece of window trim. Or, you may want the look of more expensive trim without the added costs. Layered trim may be the answer you are looking for. Simply put, you use multiple pieces of trim by installing one piece slightly over the top of another. For example, you can place a piece of crown molding around your window and then use a piece of 3/4" corner round to finish off the edge. You may choose to overlap the crown molding or not.