If you don't smoke a trick some amateur photographers use to diffuse (soften) their flashes is cutting up a plastic milk bottle. It does a nice job and can easily be made to support itself over most cameras flash bulbs.
Or, if you don't smoke, go to the off-license and buy some cheap cigarette papers and still don't smoke
You're realistically looking for any thin white material (a bedsheet, curtain, etc...) that you can use to soften and spread out the light. If you've got a bit more camera gear than some, softboxes are relatively inexpensive and work really well if you light from overhead when taking the shot (which is the set-up we use when we want to get nice photographs of the snakes).