I'm currently using a portable DVD player case that I formerly used for a 10" netbook.
It's a smidge too big, but I put it in my laptop manbag anyway, and right now it has the charger / cable in it also.
I love my M-edge Latitude jacket for my e-ink Nook - my wife bought it on ebay thinking it would fit her Kindle 2 - but the NC edition isn't available yet.
My wife just sold her Kindle 2 - planning on Kindle 3 upgrade soon - but her old K2 M-edge case doesn't fit snugly enough - I found myself worried about it falling out if given a good shake.
If I was going $30-$40 I'd probably just go $70 and get an Oberon. I'd prefer to keep it cheap though - the budget is tight.
I saw this one recommended in a thread for $8.21 - it's a Kindle 2 case though, and like the m-edge, I'm hesitant that the fit will be tight enough:
http://www.amazon.com/CaseCrown-Doub...4124167&sr=8-2