I would consider myself to almost specialize in forum/bulletin board software. My personal preference happens to be phpBB2. However when searching for some alternatives, for a user within this forum, here I stumbled upon Invision Power Board. Obviously claiming I 'specialize' in these scripts (particularly open-source) I have visied/tested/used this specific board, previously, but I was unaware that they had started charging new customers.

I would in no way object to small charges for PHP scripts and programs, but how can it be justified that a fee of 569$ USD be charged, for what I assume to be a very similar product to what I could have previously obtained for 0$ USD! :/

I am aware that this happens frequently - changing from open-source to a commercial product, with the intent of making a living from what you enjoy, but do you think that this change is a good one?