At Ultimaker.com we facilitate our operations with laser cut and 3D printed tools, such as this label dispenser. This is the first iteration, but it already works and is a nice time-saver. It's printed in exactly the width of our current labels to minimize the printing time to under 10 minutes, because we needed it fast. It's open-scad, so you can customize it for your label size. Of course a larger one will work for smaller labels as well...

Here you can see it being used by its happy user for the first time:


The same object should actually also work for postage stamps! If it doesn't it probably needs to be recompiled with a minimal change of the parameters in OpenSCAD. The wall thickness is a tat thin, but I like how you can still read the label through the top side.