So after a while of thinking, I came up with this. It a small hinged 'open box' the width of a dollar (could be modified to fit English notes). There is a small catch so that the 'box' can be closed, and the catch has to be released in order to open the box. Inside is a spring. This spring is the key to the money clip's success, as it is what keeps the money held tightly into the clip. When the box closed, the spring compresses to the size of the wad of money inside. This design allows for any amount of money to be held up to the maximum height of the box, which again, can be modified to hold more.
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