I have some clear plastic cases meant to hold paper in 8.5"x11" size. They are hinged & only about 1" thick. I got mine from the Target Dollar spot two falls ago (they had them last fall too & they sell out FAST!). I did see our Target has some in translucent green in the scrapbook section for $1.99 each. They are great because you can store stamps on both sides of the container & the cling mount sticks perfect. I have an entire 2" alphabet set all in one case!
The only issue I have had is storing clear stamps. I just put one set (an older Anna Griffin clear set) & it seems to have caused the case to warp. hmmm... Not sure about that.
I have also seen that Inque Boutique (
www.goinque.com) has some storage containers for cling stamps. They don't stay closed firmly (I have one that came with one of my large sets), but they do come in several sizes & the price is quite affordable. If you aren't transporting your stamps a lot, it will work just fine.
Hope that helps! I went throught this same search about 2 years ago!