Two super easy options:

1. Buy blank dice. They are super cheap on Amazon or at some game stores. Draw on them with a permanent marker.

2. Use regular dice, but use self adhesive labels on them (like these https://www.amazon.com/Avery-Address-Labels-Laser-Printers/dp/B00004Z5SN/). You can cut the labels to size and draw whatever you need on them.