I remember decades ago when I had no money to call my own, I would make guitar picks out of plastic nescafe caps. A friend had taught me how to do it.
It was quite simple actually, once I had obtained a template of an actual guitar pick. All I needed was a cutter and a non slip surface. I would draw the shape of the pick on the nescafe cap with a marker and then cut a little wider off the marked area with the cutter blade.
Once I got a good triangular shape, I would round off the corners and shave off just a bit of the thickness on the point I was going to use. And voila! A guitar pick that cost nothing except for a few minutes of patience 🙂