Here's an idea.

Let's have a raffle. Indefinite slots for names. One dollar a slot. You can buy as many slots as you want. At the end of a certain time period, I total all of the purchases. However much money I've raised from selling slots will determine the size of the outcome. I will then draw a number indicating the winner, who will then tell me what to make. They will receive the result, free of further charges. (Provided the shipping doesn't cost more than the total.)

How does that sound? You could potentially win a very large and detailed pipey for only one dollar. I was thinking this would happen at a convention, perhaps.