After some talking back and forth with a few trusted friends, I realized that what I was offering still wasn't really what it needed to be. So here we go, a second, and hopefully final change to commissions for the time being.
You keep the rights to everything written. What you do with it once it is written is entirely in your hands. You have all rights to the work, and it will be yours until copyright runs out. Which will be way after you're dead and gone. Point is, it's 100% yours to keep to yourself or strew around as you please.
10$ for the entire work:
This is a token payment. You give me a suggestion, vague or relatively specific, and I write it. It's for your entertainment, and perhaps to challenge me and what I write a little. Bear in mind that I'm not writing a novel for 10$, we're still talking short stories and novellas.
I will send you the story upon completion, and I will otherwise keep it to myself for a full month. I retain full and exclusive rights to the story, and keep it to myself as a courtesy to you. This means that you are not allowed to profit off the story, nor make it available at any retailer or at any public place on the internet. Once the month is over, I will publish the story if I wish to and find it suitable, or I will keep it to myself.
Of course, if you really really want a story written but can't come up with 10$, then... I don't know, try contacting me anyway. Maybe we can work something out, or I'll like your idea so much that I'll write it anyway. You never know!