For less than $4 in materials, you can make a pretty decent flash bouncer that is effective in spreading out your flash nicely, and reducing or eliminating hot spots in portrait photos. This was not my idea, but the pattern I made (below) is my version that I believe has several improvements over what I've seen elsewhere. It puts the light about 12 inches higher than it would be if the flash were facing the subject, which effectively lowers the shadows and puts them behind the subject and out of the photo. The shadows are also much softer with the bouncer.

The basic idea is to make a pattern as below, and cut out 2mm fun foam in this shape, from a piece of black and also white material. Then attach the two pieces of foam together so that the outside of the bouncer is black and the inside white. Attach velcro above and below the side slits so that you can curve the bouncer to the degree you wish. Then attach velcro on the bottom part that straps around the flash unit. I already had a piece of velcro on my 580EX flash from attaching a "Better Beamer" flash extender to it. So I attached velcro to the bouncer in a way that it also stuck to this existing piece. To fit properly on a Canon 580EX flash, the bottom part should be 9 inches wide.

Note that the measurements shown in the pattern are for a bouncer to fit aCanon 580EX flash.