This might be a stupid question (I am waiting for my Arduino stuff so I get bored), but do I need a LCD shield to be able to use a LCD screen? Or a motor shield to use motors, or GPS shield to use a GPS module?
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Short answer is no, but the different shields combine different ICs, components, connectors, etc that make it easier for you to get started working with that type of gear your first time out, or to do a quick experiment without having to reinvent the wheel each time.
Thanks.
You a cinematographer? I'm moving into that field including acting and I will soon start working on a one-man stage performance piece...oops...this is totally off topic or board context 
The problem with shields is that sometimes or maybe even often they use the same pins and so clash or are incompatible with each other. You are best off desiring your own circuit then you are in compleate control of what pins to use. However for a beginner it is a good way to get started.
Hi!
I bought a standard 20x4 character LCD screen and a I2C converter backboard from Adafruit.
This solution is affordable (total <30 USD) and requires only some headers soldering. It works like a charm.
The I2C bus uses only two pins on the Arduino board, A4 for data and A5 for clock. Because I2C is a bus, other I2C devices could be connected.