A single trick? There's a chance of nothing, and most likely it won't be very much. I say that because of how the market (in general, not just T11) is for magic tricks.
A good trick, created by someone who's known in the community, on a platform that is fairly well promoted, can sell a lot of units and potentially make thousands of dollars.
However, even a good trick, if it's by someone who isn't that well known, and on a platform that isn't very well promoted, most likely won't sell very much.
The major thing is promotion - the creator has to make sure their stuff is promoted without coming across as someone who only talks about their products.
It's best, in my opinion, not to worry about how much money you'll make from your first release. Assume the primary function will be to begin establishing a reputation. Which is what I did with Boffo. I made more from my second book, of which I have only sold about 15 copies (purposely), than I did from Boffo, of which I have sold a couple hundred copies.
Also, downloads have a reasonable shelf life of about 3 months. That's when you'll sell the majority of them, and after that it will taper off sharply.
I'm not saying this to be discouraging, just being realistic. If you establish yourself as a solid creator with your initial release, you can build from there and start getting more sales when you release subsequent products. That being said, that does rely on quality releases.