Besides my Gandalf the Grey staff, I also made a "matching" staff for Saruman the White/Many Colors.
Just like Gandalf's staff, it begins with an approximately 1" wide wooden dowel from Home Depot ($3.50), cut to be about head height.
I also used E6000, super tacky craft glue, a sheet of black craft foam from Michael's (about $1), a wooden 2" doll head from Michael's ($1.50), black, white, and silver paint, and glossy varnish.
Step 1: Glue the Doll Head to the Top of the Staff.
Use E6000 to glue the doll head (which has a flat base) to the wooden dowel. Make sure you use the glue in a well-ventilated area, and let it dry/cure for at least 48 hours before proceeding.
Step 2: Paint the Staff.
I painted the doll head with a coat of white paint, then added a very thin, slightly watered down silver layer to get the misty swirly look that Saruman's staff has.
The rest of the staff I painted black.
Step 3: Make the Fins.
Hold the staff over a piece of paper and trace its silhouette. You will use this shape to sketch the fins. I used a picture of the staff to help me estimate how long the fins should be and where the curves were. Alternately, you could print out my drawing and use it as a stencil to trace your own fins. Cut four fins from the craft foam, making all of your lines as smooth as possible.
Step 4: Attach the Fins.
Using a very tacky craft glue (Elmer's would be too watery), put a thin line of glue along the inner edge of a fin, and carefully stick it onto the staff, making sure that it stays straight. You can adjust it quickly after you put it on; if the glue smears, don't worry, since it should dry clear anyway.
Let the first fin dry. Repeat for the other three fins, making sure to line them up so that they are all at right angles to each other. If necessary, you can sketch faint pencil lines for guides on the staff.
Step 5: Varnish the Staff.
To mimic the polished metal look of Saruman's staff, I covered the whole thing in glossy varnish. I just used what I had, this Delta Ceramcoat Interior Varnish. I needed to do a couple coats to get the level of gloss I wanted, especially on the craft foam. Once the varnish has dried, be careful not to bend the fins since it will cause the varnish to crackle.
The finished staff won't be passing for a polished metal collectible anytime soon, but it's a cheap way to get the overall look of Saruman's staff!
And if you need a duo of staffs for a wizard battle, you can make a "matching" Gandalf staff!