I made this from a thrift store blazer, rather than buying fabric new. It cost about $9 (in expensive San Francisco) and I'll get another 2 hats from it, easily. If you have fallen in love with yardage, you'll need about a third of a yard -- but take the pattern to the store and lay it out there to be sure.
For the brim, I use a piece of flexible clear plastic of the kind blister packages are made from. Many packages have large flat areas from which the plastic can be reclaimed, although a lot are just too closely molded to the product. I have a stash of flat plastic for brims. Yay reuse!
The only other material needed is a yard or so of quilt binding or wide bias tape for the inner hat band. Tools required are sewing machine (although you could do this by hand as well), pins, and scissors.
Update: pix of one made from paper! http://www.flickr.com/photos/29317731@N08/sets/72157617448800455/