I'm in need of a ps3 but I don't have $200. I was wondering if anyone would sell one for 100 or less

You could go to a new and used video game store. Not GameStop. But those places sell used or refurbished game systems Or you could save up until you have enough. Just don't go to a pawn shop unless you cannot find one.
You might also be able to find a used one on Amazon.com for as little as $140.00.