This has been the top selling Calculator App on the App Store since 2011 for a reason. It does exactly what it say it will. No unnecessary complexity
*ONLY app on app store that lets you specify discounts in dollar values or percentage 
*No separate settings screen, everything is on one screen 
* Easily reset values by shaking your device 
*No ads or pop ups
* Easy to whip out and quickly calculate how much you have to pay 
* No one wants to muck around with multiple screens when they are out shopping 
* This is not one of those apps you need a phd to figure out..download and become an expert in less than a minute.