@U2Desire, I have used both
juice Grinder, and
JuiceCalculator (that's the one
@Burnie recommended).
@ShowerHead is correct, in that one must "donate" a minimum amount in order to have the inventory management feature, for more than two hours.
After using both, I settled on JuiceCalculator (aka: JC), as I didn't like the inability to remove unused flavor fields in
juice Grinder, and I
really didn't like the "hostageware" nature of the inventory management. Additionally, JC was written by one of ECF's own (
@HotRod19579), and has a great support thread here on ECF (same link).
JuiceCalculator is truly free; by which I mean
all of its features and functions are fully usable right from the get-go. The author does accept donations, but there are no repetitive "nag screens" that continue to pester you every time you start it up (as I recall; it only appears once during installation). Documentation is very good; especially for freeware.
Some, who have tried both, find Juice Grinder a bit more intuitive to get started, but that was not my own experience. If you are willing to read the "Getting Started" portion of the documentation (2-3 minutes?); it seemed like a pretty straightforward process to me. It has been my only calculator for about 2 years now, and it will remain so for the foreseeable future.