[Q] Reverting Back to Stock topic

Hello, I am still learning about custom ROM's, boot loader, etc, so I apologize if my question sounds like a noob one. I have the S III and I have put a custom ROM, boot loader, Kernal, (and radio?). I want to put my phone back to a stock ROM and everything else as I want to sell it on ebay or somewhere else. Can anyone point me to where I can find the stock ROM's and other items to bring back my phone to its "Original" state (or whatever state it would be in if it were to receive the Verizon OTA updates?)

Thanks for your help!