At that point just pay me.

If my normal billable rate is 70$ an hour I might offer a discount if your project is really neat.

But I've never seen that, I've seen people wanting to me to sign contracts would say I will donate time, and these are never people who are realistic about what their chances are. You get all this hype where they claim someone offered them 100K just for the idea, but when you ask for $100 a month to host the server they don't have it .

I was part of a group that did something like this. We used a crypto token system where if you joined the group you got X number of tokens and you could use that to get other people in the network to help with various tasks.

Then the network would take a small percentage of equity in the companies of all the members.