I am a Smartphone “Junkie”, and my drug of choice is the Samsung Galaxy S5. I have it with me everywhere I go 24 x 7. It rarely leaves my side unless one of my kids grab it to play a song or look something up.
The is one powerful app for anyone that buys or sells anything, i.e. EVERYONE! I have it on my phone and use it all the time as a “price checker” to get a sense of the overall market average price for any item.