I'm not sure if you mean the prices themselves ($18/12) or the scheme "perpetual license + optionally updates for $x/year". Feel free to hit me up on twitter @m_herrmann.

I was thinking mostly about the $18 license. More generally though, your process on pricing in general would be cool to learn about. For instance - sources of inspiration from "the literature" (ex. Strategy and tactics of pricing), past experience, user price sensitivity testing etc.

thanks - appreciate your response and its cool to see you building and selling your software!

I see. I arrived at the $18 through trial and error. It's very new though. It used to be $14, which was way too low. Following common startup advice, I raised to $28. Sales halved so there was no advantage. So now I'm trying $18.

Right on -- thanks!