This is such a good product idea, I had to try it out. My main concern was that it would be scratchy, but the fabric doesn't irritate my skin.
On the other hand, the opening is kind of like a pillowcase, with a protective flap over it. This means the cash inside will be hard to get to. Like, really hard, and I am not able to fit a credit card in here because the opening is sewn so small. But it's good for an emergency stash or large bills you simply want to be inaccessible. You'd have to go to the bathroom or a secluded place to get to any cash stashed in this item.