You can make them using a Cricut Machine. Here's how:
Try this: https://salvagedinspirations.com/how-to-make-a-stencil-no-costly-gadgets-required/
You can print letters off the internet that you like and use them to trace your own stencils onto card stock. It is time consuming, but not difficult. You will need a good pen knife or box cutter razor. Google for lettering and the style you want.