You want cheap? I'll give you cheap.
As you probably know, California Sunbounce is a cool, high-end light mod manufacturer based in Germany. Not sure where the California part came from.
Probably weather envy. (UPDATE: Nope, but I was close!)
And I say cool not just because they like to tickle the NSFW line under the chin by running ads with nekkid mannequins in the sidebar, but because they also publish the Lighting Academy website.
[UPDATE: New mannequin -- but this time she's clothed.]
Lighting Academy is the uber-cheap cousin to CSB, where almost everything is DIY-free -- or darn near it.
This quickie DIY "Budget Flash Diffuser" is so easy to make you can whip one up on the spot as needed. It is also essentially free, if you can scrounge the hair band thingie on which the mount depends. (A ball bungee would work nicely, too.)
Efficient? Nope. But perfect to turn a bare flash into a sweet little close-up portrait light. And if you were stuck with an on-camera-only flash, it would make a pretty big difference in your tight portraits, too.
It'll hold you until you can swing a Lumiquest SB-III, but you will get some light spill out of the sides unless you get all budget crazy and spring for another sheet of dark paper to cut into gobo/wings.
If you have more time than money, take a moment to look at some of the nifty ideas on their DIY site.
:: Lighting Academy: Budget Flash Diffuser ::
:: Homepage: Lots of other DIY Goodness ::