Why The Hell Do You Capitalize Every Word? ? ? ?
You can use Temboo for free. You are just limited to 250 Choreos/month and the application key resets every month so you just need to go update the key once a month.
My understanding is that if you want to interact directly with the Google Sheets API you need SSL (with Temboo you don't). I'm doubtful that will be possible with an AVR based Arduino board and an Ethernet Shield. I remember someone was looking into doing it with ESP8266 and probably even easier with ESP32.