Arduino and USB power, what to choose
Yes, you can power the Arduino using a USB phone charger.

The Arduino Uno draws less than 100mA when connected by itself. So ideally you would want the USB phone charger to provide at least 100mA. All of the USB chargers I have come across to date provide more than 400mA. Most of the modern USB chargers provide upwards of 1A for fast charging of your phone.

A USB(2) port of a laptop can provide up to 700mA to the Arduino (500mA continuous).

In terms of the overall current draw, it really depends on what you have connected to the Arduino. LEDs generally draw 20mA or less per LED. Some screens can draw anything from &lt;100mA to a couple of amps. Most of the screens I have come across draw less than 1A. It really depends on the devices you want to connect. 

For the most part, a USB charger will be sufficient.