[Hi. I am looking around for a RFID/NFC reader for arduino and I found this one: RFID Reader - Adafruit
The question I had was will I be able to use the input pins for other things like a weight sensor, or does the shield take up all of the inputs?
Thanks! 
From the website:
This shield is designed to use I2C or SPI communication protocols. I2C is the default, as it uses fewer pins: analog 4 and 5 are used for I2C (of course you can still connect other I2C devices to the bus). Digital #2 is used for "interrupt" notification.
So in the default setup (I2C), this shield uses:
analog 4
analog 5
digital 2
All other pins can be used for other tasks.
Ok. Thanks so much!