Originally Posted by nakki

Of course, no one should be asking for prices, since Wordpress is GPL software and thus all plugins should be released (that is, if they are released) under a GPL-compatible license (says so in the WordPress codex.) This means that if you're distributing your plugin, you should release the source code to the public.

Hate to be a party pooper, but if we're using open source software, we should play by the open source rules. I've written a few custom WP plugins myself so I had to read a bit about the licensing rules, and this is exactly why I've decided not to distribute them to anyone else (yet)...