[trevelyan]

Your biggest problem is that having offered him a stake in the project, you've created a situation in which he now has a reasonable right to control over the way the source code is deployed. I'd assume your programmer set up server authentication to get visibility into the number of sales. If I was working in return for a percentage of sales I would expect a way to independently verify sales figures as well.

That is really going to limit your flexibility down the road, so it is probably easier to just develop from scratch. Perhaps you should let him know you're disappointed with how things have worked out and are thinking about getting something simpler developed by someone else. Be honest and don't come across as personally critical and the discussion may push him to finish things, or break him of the mindset that you are trying to take advantage of him.

I outsource design work on a per-project basis, by the way, and like to ask people to let me know how long they take completing the work, especially since most of the time it involves iterating a couple of times. This approach lets me figure out what their hourly take-home is when all is said and done. If it ends up being too low, I like to increase it a bit more to build good relationships. Having reliable go-to people who can take care of problems on short-notice at a low cost is a lot more valuable than losing $20 here and there over individual projects.

[indiejade]

This approach lets me figure out what their hourly take-home is when all is said and done.

What, precisely, is your "job title"?

Very very few can truly afford to "outsource" design. When you start adding metrics, time worked, etc. it's hubris. Your post started off OK but ended up badly.

When you use the words "take-home" in the same sentence as the word "hourly", you're violating some serious syntax.