Buying feat dices

[Hermes Serpent]

If you are willing to sacrifice the appropriate number of D12's then you could just use a hot craft knife to change the 11 to a Gandalf rune and a 12 to an Eye symbol. I doubt that the alteration will cause the die to land on the side away from the 11 or 12 more frequently but hey if it does that's the way the lembas crumbles.

[aramis]

The cheapest solution is to just use normal d12s. Count 1 through 10 normally. 11 is the Eye and 12 is the G-rune (or vice versa).

This is what we are doing right now. It's just that my players keep forgetting that "11 is zero" thing

Buy some d12's. Buy some paint pens, extra-fine point. Either use red or the same color as the d12 for the 11. Use gold or green (in contrast) for the 12. Or, alternatively, use a white die, and a red and green sharpie, and color the face; red 11, green 12.

Or just scrape the paint out of the numbers on the 11 with a paperclip.