i don't think that people realize how much time and effort goes into creating a program
often times you also have 2 totally different kind of people as well, 1 handling the coding backend data access etc. components, and someone else handling the user interface, it is very rare that you get a single guy that is amazing at both, generally speaking it seems that most folks fall into 1 or the other category and not both...of course there are exceptions, i have worked with an amazing web programmer that's been doing it since java in the 90s and this guys is really kick ass at interface design as well, he's the only one that really excelled at both, i've been working with programmers on various levels for about 9 years and he is the only 1!
anyways, not to get all cool story bro with my long story
it is the programmer's prerogative to charge or not to charge, they made it, it's up to them or the company that hired them, not to the end user
if you don't like that, there are plenty of free (as in beer) tools out there so you can make your own, and then make it open source and give it away, you can then move on to other things like arguing over bsd, gpl, mit licensing for your open source project, it really can be fun to create your own tools and it is a great learning experience! once you do this, you'll quickly begin to understand the amount of work and effort put in, you may find yourself actually paying for some software after that experience, who knows...
me...mine is super basic in an excel spreadsheet, it would be trivial to move it into something like filemaker but i prefer to not be bound to filemaker, the excel spreadsheet can easily get loaded into google docs which then makes it portable and accessible from all of my devices at once without need for any special software...seeing this gives me a lot of ideas on things to add to mine, my plant tracker is very very simplistic at this point, it is very evident that grow assistant has had a lot of thought put into it
think about growing your herb.
it's fun to give it away for free, i wouldn't blame a guy at all for wanting a bit of $ or something in return for it though