There are many ways to get cheap plastic for CNC routing around the house, but thought I'd share my favorite
1. Buy in bulk from Amazon or eBa
2. Go to your local hardware store and find discontinued materials (like wood filler
3. Make your own with some basic tools and skill
4. Find old windows with broken pane
5. Cut them down to size and use them as blank objects for plastic moldin
6. Use spray paint to cover the holes in the plastic (this is optional
7. Sand down any rough edges or sharp corners
cheap plastic for cnc routing