Miss Tiffany

One roll of two dice. You owe the total of the pips at her price per pip — and if the two dice MATCH, that doubles. So the cheapest roll that pays is 3 pips and the worst is double sixes at 24. She also picks a mercy rule: by default any seven clears the roll and you owe nothing, or she can narrow it to snake eyes alone, or switch mercy off so every roll pays. The dice can be rigged from Gentle to Shark, and she may keep that level hidden.