I was looking for a case for one of my older e-readers that I'm going to pass along to my son, and thought I'd look at Tanga, who have had M-Edge cases on sale in the past. Turns out that they have a number of cases available now for between $4 and $5 plus shipping. These are cases for older Kindles and Nooks. A couple of them are zippered cases which might be "generic" and might fit other devices also. I have had other M-Edge cases in the past, bought from other tanga.com sales, and have been quite pleased with them - they have been sturdy and convenient.
Not sure if this is one of Tanga's limited time sales, since there is no countdown clock on the webpage, or whether it is just closeout of what they have. In any case, it's been a while since their last M-edge sale, so I thought I'd provide this info.
Link is here:
https://www.tanga.com/products/search?q=m-edge