I know there is a million of these out there but I designed my own anyway. I wanted one that was cheap and portable but was somewhat professional looking so my clients wouldn't think I was a total amature. This diffuser is designed for the Canon 580EX II flash but could easily be modified to fit any flash, or it may not need modification at all.
Things you'll need:
Posterboard (Black), or if you can get polypropelene sheets even better. ~$1
1 12x15" frosted cutting board (thin plastic, avaiable at most dollar stores)***
Scissors or olfa blade
Ruler & Protractor (not needed if you print out the template)
Electrical Tape (preferrably black)
Velcro with adhesive backing (or you can glue it yourself)
Optional: Glue, if you want to make tabs and glue it instead of using electrical tape
***If you can't find the clear frosted cutting board you can simply cut the same shape out of the posterboard then cut a small window in it and use tissue paper, velum, or even a cutout section of a white plastic bag.
Remember, if you like this instructable please take the time to rate it.
Step 1: Supplies
The image below shows the supplies you'll need, I forgot to put the velcro and the electrical tape in the shot though ;) Also the gluestick is unused in my version but if you want you can modify the project to glue it together instead of using electrical tape.