The short of it is that it costs you nothing unless I deliver a solution.
There will be travel and accommodation costs if you’d like me to be on site, but we can also work via email or video conferencing if the nature of the work is amenable to it, in which case it costs you nothing but the time spent explaining things to me.
Should I deliver a solution to you, your cost will be a percentage of the gross from the product or service that you will make available to the market. We will agree on the percentage ahead of time.
If your project isn’t of a commercial nature, then we’ll agree on some other pricing (hourly, daily or fixed fee) ahead of time, but once again, you won’t pay a thing (other than travel and accommodations, where applicable) if I don’t deliver a solution to you.