Doesnt work at all?

I just downloaded this app to keep me in budget while shopping and its very generic. The main thing is that the calculator doesnt even work right off the bat? Whats up with that? Im inter IOS 10 for iPhone. It would also be nice that if I can add actual names to each item and not just show a total. Like cereal $3.50 a scanner of some sort to be able to scan the price or something would be great. But since I just paid for this App u need to get the tax part to work or I want a refund.

ProcGirl about Ez Shopping Calculator, v1.2