You’re really going to shake up the plugin market. Good on you. 
And I agree with you. Some of the current plugin prices a way over the top.
But I can understand the reason behind the prices for some too.
My air date/time picker plugin (which is free btw) has over 500 lines of code and i’ve spent more than 100 hours on it.
I have some plugins too that are just about 20 lines of code and i’ve spent just like 3hrs on them.
Btw I already published a version of your Better Date picker on the plugin store for free more than a year ago.
(it was initially paid but made it free in a few days after i published it).