My point about charging for time and effort was really that there are two models. The service model where you agree to provide something for a price and then provide it, and the product model where you produce something and then ask someone if they want one.

In the first you can charge based on time irrespective of the value, in the second you need to factor in your development costs in the sale price then figure out if you can sell enough at the necessary price to make a return. If you can’t then all your time and effort does indeed go unrewarded.

What you have come up with seems entirely reasonable. Anyone who wants the code can get it and end users pay for your product.

The downside is that your entire model relies on trust. There are a number of whatifs that kill your revenue stream:

First: what if someone forks it, releases it, and promotes it better than you? You seem like the untrusted copy instead of the original.

Second: What if WordPress 3.0 has your code added to it?

Of course, licensing doesn’t prevent this, it just means you can have your day in court, if you can afford it, to try and reclaim revenue, but GPL makes it easy to happen. That is why the premium themers are promoting support services so heavily.

There are people who already successfully charge for plugins and they do it by just not putting it on wp.org. In effect they sell to people who sell it on to end users and it never goes any further so it is entirely feasible as long as the target market is right.