If you go back to the homepage, he's offering the plugin for commercial use for $37. I like this idea of monetizing the use of plugins, especially ones so well-built. (He's also offering direct support for $17, another interesting idea.)
Indeed. It's such a frictionless purchase that he'll be laughing all the way to the bank.
For some reason in my mind I had always assumed that open source type things have to be done for free: the building, the support, etc. Seeing someone doing something others helps put that in perspective.
Or, in short: I wish I was smarter about it and more business-savvy.
Just keep the amount reasonable in relation to the product and don't make me jump through hoops. I.e. just link directly to paypal and if you want to ask me any questions then put that form after the checkout-process where I'm free to ignore it.
Here is a non-solicited biz-savy tip: Tell us the names of your plugins.